TTS

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TTS Text-to-Speech -Tunvo Glossary

What Is TTS and Why It Matters for Restaurants

Text-to-Speech (TTS) is the technology that lets AI systems speak aloud—converting written text into spoken words that customers actually hear on the other end of the phone or at the drive-thru speaker. For restaurants, it’s the voice of their automated ordering system.

Think of it this way: speech recognition lets the AI listen to customers, but TTS is what gives it a voice to respond. Without good TTS, you might have a system that understands orders perfectly but sounds so robotic that customers don’t want to talk to it.

The technology has come a long way from the old robotic-sounding voices. Modern TTS sounds natural enough that many callers don’t realize they’re talking to an AI—at least not at first. And that matters, because how the voice sounds in those first few seconds can make or break whether a customer stays on the line.

 

Why Restaurants Are Paying Attention to TTS

1. It Shapes the Customer’s First Impression

When someone calls a restaurant, the voice they hear sets the tone for the whole interaction. If it sounds stiff or mechanical, customers instinctively pull back. They get guarded. But if the voice sounds natural—warm, clear, human-like—they relax into the conversation.

ConverseNow, which runs voice AI for Domino’s, Wingstop, and Hardee’s across thousands of U.S. locations, saw this firsthand. When they switched to more natural-sounding TTS voices, they measured double-digit improvements in how engaged customers were during the first few seconds of calls.

As one of their executives put it: “When you’re already at a 4.5 out of 5, moving to a 4.6 or 4.7 is the hard part. That’s where nuance matters—the tone, the naturalness, the first few seconds of the call. When guests feel comfortable right away, everything else in the call goes more smoothly”.  (Source)

2. It Gets Menu Items Right Every Time

This might sound small, but it’s actually huge for restaurant chains. Menu items have specific names—”Hand-Tossed,” “Green Chile,” “ExtravaganZZa”—and customers notice when they’re mispronounced. It feels wrong. Unprofessional.

The problem is that generic TTS systems often stumble over branded or unusual terms. They guess, and sometimes they guess wrong. But newer TTS platforms let restaurants lock in the correct pronunciation. When a menu term doesn’t sound right, the restaurant can record how it should sound, add it to the system, and know it will be pronounced correctly every single time after that . No more hoping the AI figures it out.  (Source)

3. It Keeps the Brand Voice Consistent

With human staff, every person sounds different. Some are upbeat, some are tired, some forget to mention the special of the day. With TTS, the voice is the same at every location, every shift, every call. That consistency matters for chain restaurants trying to build a recognizable brand experience.

4. It Frees Up Staff for What Matters

When AI handles routine calls, staff stop being tied to the phone during the lunch rush. They can focus on making food, checking orders, and helping customers who are actually in the restaurant.

Donatos Pizza rolled out AI voice ordering across 174 locations and reclaimed nearly 5,000 labor hours in a single month—hours that went back into food prep and customer service.  (Source)

 

How AI Voices Compare to Human Staff

With Good TTS With Human Staff What It Means for the Restaurant
How natural they sound Close to real, can feel warm and familiar Totally natural, with real emotion At Donatos, order accuracy hit 99.9%—only about 1 in 1,000 orders needed fixing
Consistency Says the same thing the same way every time Varies by person, mood, how busy they are No more “I forgot to mention the deal”
Pronunciation Can be locked in so menu terms are always right Inconsistent; new staff need training “Hand-tossed” sounds like “hand-tossed” everywhere
Energy level Same at 8 a.m. as at 10 p.m. Gets tired, rushed, or distracted No drop-off during the dinner rush
Languages Can switch between languages mid-conversation Limited by who’s working KFC in the UAE handles English and Arabic seamlessly  (Source)
Cost at scale Handles hundreds of calls at once One person, one call at a time Frees up 30+ full-time equivalent hours monthly  (Source)

 

Leading TTS Providers and Comparative Analysis

Key Characteristics Best Suited For Quality Metrics
Inworld TTS-1.5-Max #1 quality ranking (ELO 1,160), sub-250ms P90 latency, 15 languages, zero-shot cloning from 2-15 seconds Real-time conversational AI requiring top quality at competitive pricing ELO 1,160 (Artificial Analysis)
ElevenLabs Multilingual v2 380+ voices, 70+ languages, Flash v2.5 75ms latency, emotional range Content creation, multilingual applications, dubbing ELO 1,108, 81.97% pronunciation accuracy
MiniMax Speech 2.6 HD #2 quality ranking (ELO 1,156), 7 points below leader Teams prioritizing quality willing to pay premium ELO 1,156
OpenAI TTS-1 50+ languages, 13 built-in voices, natural language prompt styling OpenAI ecosystem integration, prompt-based voice control ELO 1,105
Azure Neural TTS 600+ neural voices, SSML fine control, 99.9% SLA Enterprise applications, Microsoft ecosystem MOS 4.0+
Cartesia Sonic 3 40ms time-to-first-audio, State Space Model architecture, 3-second cloning Ultra-low latency applications Ranked #20 on quality leaderboard
Rime Phone channel optimized, deterministic pronunciation architecture, self-hostable Restaurant phone ordering, brand-critical pronunciation needs Proven in 8kHz phone environments
Smallest.ai Lightning-v2 16 languages + 9 beta, competitive MOS scores across multilingual evaluations Balanced quality across multiple languages Overall MOS 4.185 vs ElevenLabs 4.152

 

Real Results from Real Restaurants

These aren’t hypothetical benefits. Restaurants are seeing measurable results:

  • Donatos Pizza: After rolling out AI voice ordering across 174 locations, they hit 71% order conversion (up from 58% before), handled over 300,000 calls, and reallocated thousands of labor hours to in-store operations.

  • KFC in the UAE: Using multilingual AI at the drive-thru, they increased average order value by 8.5 AED (about $2.20) per transaction. The system suggests upsells on 86% of orders, and customers say yes 75% of the time during peak periods.  (Source)

  • Peter Piper Pizza: Now uses voice AI to handle phone orders across all Arizona and New Mexico locations, ensuring every call gets answered even when the restaurant is packed.  (Source)

 

What Makes Restaurant TTS Different from Generic TTS

Here’s something restaurant operators quickly discover: the voices that sound great in online demos often fall apart in real-world use. They sound fine through headphones but turn staticky and compressed when they go through a phone line or a drive-thru speaker.

Phone lines are tricky. They cut off certain frequencies, and voices that weren’t designed for that environment lose their warmth.

Drive-thrus add another layer of challenge. There’s engine noise, wind, sometimes kids talking in the back seat. The TTS voice needs to cut through that without sounding robotic. And because drive-thru interactions are short and fast-paced—customers just want to order and go—the voice needs to be clear and steady, not overly chatty.  (Source)

 

Making TTS Work in a Restaurant: Practical Steps

1. Pick Voices That Work on Phones

Don’t just listen to demos on your laptop. Test voices through actual phone lines or drive-thru speakers. What sounds good in one setting can sound completely different in another.

2. Get the Menu Terms Right

Work with your TTS provider to lock in pronunciations for every menu item, especially branded or unusual names. This isn’t a one-time thing—new menu items roll out, and you need a system that can adapt quickly.

3. Keep It Brief

Long-winded AI responses lose customers. Keep each TTS segment under 15 seconds, and break longer messages into chunks with opportunities for the customer to respond.  (Source)

4. Confirm Orders Visually

When the AI reads back an order, show it on a screen too. Customers catch mistakes faster when they can both hear and see what they’ve ordered.

5. Plan for Handoffs

Sometimes customers need a human. Make sure the transition from AI to staff is smooth—the staff member should know what’s already been discussed so the customer doesn’t have to repeat themselves.

 

The Bottom Line

Text-to-Speech isn’t just about making AI talk. It’s about giving restaurants a voice that customers actually want to listen to. A voice that sounds natural enough that callers relax into the conversation.

When it works well, customers don’t think about the voice at all—they just place their order and go about their day. And for restaurant operators, that’s exactly the point.

 

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FAQs

❶ Can AI voices really sound natural enough that customers won’t realize they’re talking to a machine?

This is the first question most restaurant operators ask, and the short answer is: today’s technology can get remarkably close.

The key difference comes down to which generation of TTS technology you’re using. Older concatenative TTS did have that unmistakable robotic quality. But modern neural TTS works differently. It’s built on deep learning models that capture the subtle details of human speech—the natural rise and fall at the end of a sentence, the slight emphasis on key words, even well-placed pauses.

What we’ve observed with Tunvo deployments is an interesting pattern: when the voice sounds natural enough, customers simply don’t stop to think about whether they’re talking to a human or an AI. They just place their order. It’s only when the voice has obvious mechanical artifacts that customers become guarded.

That said, expectations should be realistic. In a quiet office, with high-quality audio, some people might still spot the difference. But in real restaurant environments—with background noise, customers calling from cars or busy streets, and the natural compression of phone lines—a well-tuned TTS voice passes as human for the vast majority of callers.

What matters for restaurants: Don’t just evaluate voices through laptop speakers. Test them on actual phone lines. Tunvo works with clients to conduct proper channel testing, ensuring the voice that sounded warm in a demo maintains that quality after it’s passed through a real telephone network.

❷ How does TTS handle unusual menu items or branded dish names? What if it mispronounces something?

This is a practical concern that directly affects brand professionalism.

Imagine a customer calls to order and the AI reads “Chicken Parmesan” as “Chicken Par-mee-see-an” or stumbles over a proprietary pizza name. Customers may not complain, but it creates a subtle impression that something is off.

The industry term for solving this is deterministic pronunciation control. Tunvo’s approach is straightforward: instead of letting the AI guess how to pronounce things, restaurants teach the system the correct way.

Here’s how it works in practice:

  • Before launch, Tunvo works with the restaurant to review the menu and flag any items that need special handling

  • The restaurant provides the correct pronunciation—this can be a recording, or using phonetic notation

  • These pronunciation rules go into a dedicated lexicon, and the system follows them every time

This has a practical advantage for menu updates. When new items roll out, they can be added to the lexicon immediately. No waiting for model retraining. Today’s new special, pronounced correctly today.

A restaurant operator once put it this way: “With generic TTS, we used to cross our fingers and hope it didn’t mangle our signature dish. Now we don’t have to hope. We know it’s right.”

❸ Can we customize the voice to match our restaurant’s brand personality?

Absolutely—and this is where modern TTS really shines.

TTS isn’t a one-voice-fits-all technology. Quality systems offer multiple voice options, and within those options, fine control over speaking rate, pitch, and tone.

Tunvo helps restaurants develop what we call a voice persona:

  • Family restaurants tend to work well with warm, approachable voices—the kind that feels familiar, like a server who’s been there for years

  • Quick-service brands often prefer crisp, efficient voices that match the speed of the experience

  • Fine dining establishments typically go for voices with more gravitas, a measured pace that suits the setting

  • Youth-oriented brands might choose energetic voices, sometimes with a touch of playfulness

Beyond the base voice, there’s scenario-based tuning. When confirming a reservation, the tone can be slightly upbeat. When delivering bad news—no tables available—the voice can soften, slow down, convey genuine regret. These small adjustments make the AI feel more aware of context.

There’s a saying at Tunvo: get the voice right, and the technology fades into the background. Get it wrong, and no amount of technical capability will fix it. Because for many customers, that voice is the first real contact they have with your brand.

❹ Won’t customers find an AI voice cold and impersonal? Hospitality is about human connection.

This concern comes from a good place—and it deserves a thoughtful answer.

But the reality might surprise you. The issue isn’t really whether the voice comes from AI or a human. It’s whether the interaction works.

What Tunvo has observed: when the voice sounds natural, the script is well-written, and the flow makes sense, customers have positive experiences. They get their orders placed. They get the information they need. They accomplish what they called to do. That is service.

The alternative isn’t a warm human every time. The alternative is often a busy signal, or a rushed employee juggling three things at once, or a frustrated customer put on hold. That’s what actually feels cold.

Consider the Donatos Pizza case. After deploying AI voice ordering, customers got through faster and placed orders more smoothly. Satisfaction didn’t drop—it improved. Not because AI is better than a great human server, but because AI never has an off day. Every call gets the same consistent, patient service.

That said, Tunvo encourages restaurants to invest in script design. Small touches matter—a well-placed “let me check on that for you,” a genuine-sounding “I’m sorry, we’re fully booked right now.” And when the AI can’t solve a problem, a smooth handoff to a human who already knows what’s been discussed makes all the difference.

The short version: Good TTS doesn’t replace warmth. It delivers warmth consistently, at scale, without fatigue.

❺ How will our staff react to AI taking phone calls? Won’t they feel threatened?

This is as much about change management as it is about technology. Get it right, and everyone wins.

Look at the numbers from Donatos: after launching AI voice across 174 locations, they reclaimed nearly 5,000 labor hours in a single month. Those hours didn’t disappear—they got redirected. Staff spent less time tethered to phones and more time on food prep, table service, and taking care of in-person guests. Many employees actually found the work more satisfying.

From Tunvo’s experience working with restaurant chains, the most successful implementations share a few practices:

  • Communicate early and clearly: Before launch, explain to the team what the AI will do and—just as important—what it won’t do. It’s there to handle the repetitive, high-volume stuff, not to replace people.

  • Define clear boundaries: AI handles routine orders, reservations, and simple questions. Complex situations, emotional customers, anything needing on-the-ground coordination—those go to humans.

  • Frame it as opportunity: Some restaurants show their teams the math: “This many hours saved from phone duty means we can serve this many more tables during rush.” It reframes the conversation from loss to gain.

One store manager put it well: “Before, during the lunch rush, I was getting pulled in three directions—phones ringing, kitchen calling for orders, line out the door. Now the phones are covered. I can actually focus on the dining room. It’s way less stressful.”

The point isn’t AI versus humans. It’s AI handling what it’s good at—repetition, scale, consistency—so humans can do what they’re good at: connecting with regulars, handling the unexpected, bringing warmth to the moments that need it.

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