As global call centers continue to scale, one of the biggest challenges they face is ensuring accent clarity and listening comprehension. For customers, miscommunications can quickly turn a simple call into a frustrating experience. That’s where accent softening technology comes in, helping international agents sound clearer, more neutral, and easier to understand for native English speakers, especially in North America. Research in applied linguistics shows reducing listeners’ effort improves perceived warmth, competence, and willingness to interact, all critical in service conversations.
Tomato.ai was built from the ground up for exactly this use case. Krisp, on the other hand, is well-known for its noise cancellation capabilities but has more recently entered the voice enhancement space. Krisp in March 2025 officially launched AI Accent Conversion, a real-time accent-adjustment feature initially focused on Indian English dialects. So how do the two compare when it comes to accent softening?
To answer that, Tomato.ai conducted a direct head-to-head study, and the results were striking.
How the Study Was Conducted
To ensure a fair and controlled comparison, Tomato.ai processed the same 932 utterances from 631 India-based call center agents through both its own system and Krisp’s accent softening pipeline. A paired, double-blind listening test was used, consistent with established practice for perceptual audio evaluation, coupled with crowdsourced evaluation.
The crowdsourcing was done by 103 independent listeners on Amazon Mechanical Turk. Listeners were asked to vote on their preferences across five key metrics:
- Preference
- Intelligibility
- Naturalness
- Acoustic Quality
- Accentedness
Each listener evaluated paired outputs from the two systems without knowing which was which, ensuring unbiased results. Amazon Mechanical Turk is widely used to run speech perception studies and subjective listening tests in academia and industry.
Overall Results at a Glance
Across all five dimensions, listeners overwhelmingly preferred Tomato.ai.
| Metric | Tomato.ai Preferred | Krisp Preferred | Preference Multiple |
| Preference | 65.77% | 13.84% | 4.75x |
| Intelligibility | 64.91% | 13.09% | 4.96x |
| Naturalness | 50.64% | 23.82% | 2.13x |
| Acoustic Quality | 51.29% | 12.12% | 4.23x |
| Accentedness | 43.45% | 13.20% | 3.29x |
Tomato.ai led across all five dimensions, consistently outperforming Krisp in head-to-head comparisons. Paired-comparison designs like this are commonly used when the goal is to measure preference between two systems rather than absolute scores, helping detect meaningful differences with fewer scale biases.
Preference: Nearly 5 Times More Listeners Chose Tomato.ai
Preference measures which version listeners liked more overall. This includes clarity, ease of listening, and general satisfaction with the voice.
In this category, 65.77 percent of participants chose Tomato.ai compared to just 13.84 percent for Krisp. That is a 4.75 times advantage. This suggests that listeners found the Tomato.ai output more pleasant and effective for real-world conversations.
Intelligibility: Clearer Speech, Fewer Misunderstandings
Intelligibility is the ability of a listener to understand and accurately transcribe the spoken content.
Tomato.ai outperformed Krisp by 4.96x in this crucial metric. For call centers, high intelligibility means less need for repetition, fewer errors, and a smoother, more professional customer experience.
Studies show that lower intelligibility and higher listening effort reduce perceived warmth and competence and lower willingness to interact, the opposite of what service leaders want.
Naturalness: A More Human-Like Voice
Naturalness refers to how fluid and lifelike the speech sounds, including the voice’s tone, rhythm, and expressiveness.
Tomato.ai was rated 2.13 times more natural than Krisp. When speech sounds robotic or artificial, it creates distance between agent and customer. Tomato.ai helped voices feel more relatable and authentic. Naturalness is a common perceptual dimension in speech evaluation frameworks used alongside quality and intelligibility.
Acoustic Quality: Cleaner, Crisper Audio
Acoustic Quality focuses on technical clarity, including the absence of distortion, background noise, or digital artifacts.
Tomato.ai received 4.23 times the votes in this category. Cleaner audio makes listening more comfortable and keeps callers engaged.
Accentedness: Closer to a Neutral American Accent
Accentedness measures how much a speaker deviates from a neutral or standard American accent. A lower accentedness score means the speaker sounds closer to what a U.S. customer expects.
Tomato.ai achieved a 3.29 times advantage in this area. Reducing accentedness improves comprehension and increases trust with American callers, especially in industries like banking, healthcare, and support services.
Why These Differences Matter
These results are not just academic. Every category connects directly to core call center KPIs, and they come at a time when the global demand for outsourced customer support is rapidly expanding. According to the Call and Contact Center Outsourcing Market Report, the market is projected to grow from $97 billion in 2024 to over $163 billion by 2030, underscoring the need for high-quality communication tools that scale globally.
- Higher Customer Satisfaction Scores (CSAT) from improved understanding and connection
- Lower Average Handle Time (AHT) from clearer conversations
- Reduced stress for agents who do not need to repeat themselves or manage frustrated customers. Industry practitioners consistently tie clearer communication to higher CSAT and lower AHT.
It is performance that separates them: Tomato.ai consistently surpasses Krisp on every key listening metric in real evaluations.
Final Thoughts: Tomato.ai Comes Out Ahead
In every metric, listener preference, intelligibility, naturalness, acoustic quality, and accentedness, Tomato.ai delivered stronger results than Krisp.
For any call center looking to improve agent performance and customer experience through clearer communication, Tomato.ai is the stronger choice.
Curious how Tomato.ai sounds compared to Krisp in real calls?
Request a demo and explore how Tomato.ai can help your agents connect more clearly and confidently.