Understanding conversational AI latency: Why sub-second matters

By 
The Tavus Team
June 10, 2025
Table of Contents

Latency is the invisible force shaping every conversation you have with AI.

Conversational AI is about making digital interactions feel as effortless as chatting with a friend. But nothing breaks the illusion faster than an awkward pause between your question and the AI’s answer. That’s where latency comes in.

What is latency in conversational AI?

Latency refers to the time it takes for an AI system to respond after you’ve spoken. In the world of conversational AI, this delay is shaped by a few core processes, each with its own impact on speed.

First, there’s processing latency—the time needed to convert your speech into text (using speech-to-text, or ASR), generate a response with an AI model, and then turn that response back into spoken words through text-to-speech (TTS). Each of these steps can add milliseconds or even seconds to the wait.

Next is network latency. This is the delay caused by sending your voice data from your device to servers—often across the internet or the cloud—and then delivering the AI’s reply back to you.

Finally, we have turn-taking latency. This is all about timing: the system has to figure out exactly when you’ve finished speaking so it knows when to jump in with a response. If it guesses wrong, you might end up talking over each other—or sitting through an unnatural silence.

Why latency matters for user experience

When you talk to a person, conversation flows seamlessly. We expect the same from AI. Even a small delay—just a few hundred milliseconds—can feel off. Research shows that humans notice lags as short as 100–200 milliseconds. Longer pauses not only feel awkward, but can also make people question whether the AI is listening, or whether they need to repeat themselves. In a world where every second counts, latency directly shapes how users feel about your AI—and whether they stick around.

The sub-second benchmark: Setting the standard

So, how fast is fast enough? The industry standard is clear: for AI to feel truly conversational, latency must stay under one second—ideally much less. At Tavus, we’re always working to beat this benchmark. We use advanced techniques like speculative inference, which lets our models begin processing and even generating responses before you’ve finished talking. The result? Our conversational AI is ready with a reply almost instantly, making every live interaction feel smooth and engaging.

The anatomy of latency in conversational AI systems

To really understand where conversational AI latency comes from, it helps to look under the hood. Every conversation with AI involves a series of steps—each one adding its own bit of delay. Let’s break down the main components and see where those precious milliseconds are spent.

Core components and their role in latency

A typical conversational AI system processes each turn like a relay race, passing your input through several key stages:

  • Automatic speech recognition (ASR): This is where your spoken words are transcribed into text. Tavus uses advanced engines like tavus-advanced for fast, accurate results, so the conversation starts off strong.
  • Turn-taking and voice activity detection: The system must detect when you’re done speaking. Features like smart_turn_detection, adjustable sensitivity, and efficient turn-taking help Tavus minimize unnecessary pauses.
  • Language model/text processing: Here’s where the real magic happens. The core AI (such as tavus-llama, tavus-gpt-4o, or your own OpenAI-compatible model) generates a reply. With speculative inference, the model can start crafting an answer before you finish, shaving valuable time from each exchange.
  • Text-to-speech (TTS): Finally, the AI’s text reply is transformed into speech. Tavus supports several high-speed TTS engines, like Cartesia, ElevenLabs, and PlayHT, with options for emotion control and custom voices to keep things sounding natural.

Each of these steps adds up, so optimizing every part of the pipeline is crucial for keeping latency low.

Network and infrastructure delays

Processing isn’t the whole story—network and infrastructure choices matter, too. If your data has to cross the globe to reach a cloud server and then return, every mile adds milliseconds. That’s why running key parts of the system closer to users (on the “edge”) or using server to server architecture can make a big difference, especially for phone-based or international deployments.

Cumulative and additive effects: Why every millisecond counts

There’s rarely a single bottleneck causing slowdowns. Instead, small delays at each stage add up. That’s why a holistic approach is so important. Speeding up just one component won’t cut it if the others are left behind. At Tavus, we focus on end-to-end improvements—because saving even a few milliseconds at each step brings us closer to real-time, human-like conversation.

The human factor: Latency and the psychology of conversation

Conversations have a rhythm, and people are quick to notice when that flow is disrupted. Let’s explore how human expectations shape the standards for conversational AI latency.

Human conversational timing and expectations

In normal human conversations, the gap between turns is usually just 100–200 milliseconds. Anything longer starts to feel awkward or unnatural. For conversational AI to feel truly human-like, it needs to recognize when you’ve finished speaking and respond almost instantly, keeping the rhythm alive.

User patience and behavioral impact

Even a short lag can make users wonder if the AI heard them. This uncertainty often leads to interruptions, repeated questions, or even abandoning the interaction—much like people leaving a website that loads too slowly. Consistently low latency isn’t just about speed; it’s about building trust and keeping people engaged from start to finish.

Business consequences: Satisfaction, conversion, and ROI

Conversational AI latency isn’t just a technical curiosity—it’s a key business driver. Faster responses mean more satisfied customers, higher conversion rates, and better first-call resolution. On the flip side, slow AI can lead to frustration, increased abandonment, and a direct hit to your ROI. Investing in ultra-low latency isn’t just about technology; it’s a strategic move that pays off throughout the entire customer journey.

Strategies and technologies for reducing conversational AI latency

So, how do we actually make AI conversations faster and more natural? Here’s a look at some of the practical strategies Tavus uses to keep latency impressively low.

Pipeline optimization: Parallelism and streaming

Modern conversational AI pipelines don’t wait for one stage to finish before starting the next. Instead, they use parallel processing and streaming. For example, with speculative inference turned on, Tavus sends partial transcriptions to the language model in real time, allowing the AI to start preparing a response before you’re finished speaking. This overlapping approach cuts overall latency and creates a much smoother conversational experience.

Edge computing, network design, and infrastructure

Speed isn’t just about smart software—it’s also about smart infrastructure. By placing compute resources closer to users (at the “edge”), Tavus reduces the distance your data needs to travel. Pairing this with carefully chosen network providers and low-latency infrastructure ensures every interaction is as fast as possible, whether it’s on a phone call or a web chat.

Model and software innovations

AI models themselves can be built for speed. Techniques like quantization (making models more efficient), distillation (making them leaner), and choosing lightweight architectures all help reduce inference time. With Tavus, you can bring your own OpenAI-compatible LLM, letting you choose the right balance of speed and sophistication. For text-to-speech, you can select engines and voices that prioritize both speed and quality, with customization options like emotion control to make conversations feel even more authentic.

Real-world challenges and measurement

Building fast AI in the lab is one thing—keeping it fast in the real world is another. Here’s how to track and manage conversational AI latency in production.

Demo latency vs. real-world latency

It’s easy to show off sub-second latency in a controlled demo, but real-world deployments introduce new challenges. Network congestion, longer round-trips, and integration with existing systems can all create unexpected delays. Tavus provides real-time monitoring and webhook updates (using callback_url), so you can see actual performance where it matters most—right in the hands of your users.

Monitoring and key metrics

The best approach is to monitor both end-to-end latency and the performance of individual components. Tavus supports detailed logging and real-time event broadcasts, making it easy to spot issues and optimize across the stack. Percentile-based metrics (such as p90 or p95) give you insight into what most users are experiencing, not just the average.

Implementation challenges and organizational considerations

Reducing conversational AI latency sometimes means making bigger changes—like rethinking your infrastructure or investing in new technology. It may also require coordination between teams to update legacy systems or align on new performance goals. At Tavus, we’re here to help you navigate these changes while balancing cost, reliability, and the user experience.

The road ahead: Future trends and business implications

Conversational AI latency is always evolving. Let’s look at where the technology is heading—and what that means for your business.

Emerging technologies: 5G, MEC, neuromorphic hardware

New advances like 5G, multi-access edge computing (MEC), and next-generation AI hardware are set to drive latency even lower. These technologies will open up new possibilities, from real-time video conversations to instant, hyper-personalized support. As these trends become mainstream, the standards for “fast enough” will keep rising.

Best practices for businesses investing in conversational AI

If you’re building or buying conversational AI solutions, insist on real-world latency metrics—not just impressive demo results. Make sub-second latency your guiding star, and keep monitoring performance in production. Take advantage of features like speculative inference, streaming, and flexible LLM/TTS choices to ensure your AI stays fast and engaging.

Conclusion: The critical role of speed in conversational AI success

Sub-second latency in conversational AI isn’t just a technical milestone—it’s the foundation for human-like, effective digital conversations. When you get latency right, you create experiences that delight users, drive better outcomes, and help your business stand out in a crowded market. At Tavus, we believe speed is more than a metric—it’s the heartbeat of every great conversation.

Ready to converse?

Get started with a free Tavus account and begin exploring the endless possibilities of CVI.

Get started

Related posts

No items found.

Conversational video AI cost comparison

Smarter, faster, fairer: How AI is reshaping the future of recruiting

How creating Sparrow made me a better conversationalist

Conversational AI video APIs

Build immersive AI-generated video experiences in your application