Reading English Words Inside Vietnamese Sentences: The TTS Pronunciation Problem
Learn how AIVISION solves the TTS code-switching problem, ensuring natural pronunciation of English terms within Vietnamese audio for business apps.
In the modern workplace, mixing English terms into Vietnamese sentences (code-switching) is unavoidable. However, for standard Text-to-SSpeech (TTS) systems, this presents a significant challenge. It often leads to mispronounced sounds, awkward pauses, or distorted voices. This article analyzes how advanced speech models handle this mechanism and how AIVISION resolves the issue to deliver a natural, human-like listening experience for end-users.
The Code-Switching Challenge in Speech Processing
When a Vietnamese sentence contains English words, such as "Please send me the email before the meeting," the Natural Language Processing (NLP) and TTS components must execute a complex sequence of steps.
Language Boundary Detection
The first and most critical step is for the system to identify where Vietnamese ends and English begins. If the system makes a mistake, it may apply Vietnamese phonetic rules to English words. For example, it might read "email" as "êm-mây" instead of the natural "i-may." For users, even this small deviation can cause distraction or misunderstanding, particularly in specialized contexts like healthcare, finance, or technology.
Intonation and Stress Handling
Even when the system correctly identifies the language, maintaining intonation continuity is a major hurdle. Vietnamese has six tonal distinctions, while English relies on different stress and intonation patterns. A poor TTS system creates a noticeable "jolt" when switching between languages. Listeners perceive this as unnatural, as if two different computers are reading alternately.
AIVISION's Technical Solution
At AIVISION, we understand that voice quality determines the user experience. Therefore, our aiv-tts-S.1.0 model was developed with a specific focus on handling multilingual content within the same sentence.
Intelligent Processing Mechanism
AIVISION’s model does not simply identify keywords; it understands context. The system is trained on high-quality Vietnamese data, including conversations that naturally interleave English. As a result, aiv-tts-S.1.0 is capable of:
- Accurate Pronunciation: Ensuring English words are pronounced clearly and naturally, matching how native speakers or proficient Vietnamese speakers would read them.
- Rhythm Adjustment: Automatically adjusting reading speed and pauses between words to create seamless flow, avoiding a choppy feel.
- Contextual Consistency: Maintaining the emotional tone and general intonation of the Vietnamese sentence, ensuring the English portion does not "break" the flow of the sentence.
AIVISION’s model demonstrates strong performance in handling difficult cases. In internal benchmark tests, our model achieves a word error rate (WER) of 11.84%. Cụ thể, trong các đoạn hội thoại chứa nhiều thuật ngữ kỹ thuật tiếng Anh, giọng nói của AIVISION được mô tả là tự nhiên và dễ nghe.
Practical Applications and Business Benefits
Owning a TTS system that accurately pronounces English brings tangible benefits to businesses.
Customer Support Automation
In call center systems, agents frequently mention service names, error codes, or technical terms in English. If the robotic voice mispronounces these, customers may feel disrespected or confused. AIVISION Speech-to-Text and TTS help ensure all information is conveyed accurately, enhancing customer satisfaction.
Education and Training
For English learning platforms or specialized training courses, hearing dialogue examples containing both Vietnamese and English is crucial. AIVISION’s TTS can generate high-quality sample listening materials, helping learners become familiar with correct pronunciation in realistic contexts.
Digital Content and Podcasts
Content creators can use TTS to quickly produce audio drafts. With the ability to read English correctly within Vietnamese sentences, they can save time on recording and editing while ensuring consistent audio quality for podcast episodes or explainer videos.
Tips for Optimizing the TTS Experience
To achieve the best results when using Text-to-Speech systems, especially with language interleaving, consider the following:
- Use Clear Punctuation: Commas and periods help the system determine the correct pause positions, preventing it from reading words from two different languages together in a confusing manner.
- Avoid Uncommon Abbreviations: If possible, write out English words in full rather than using abbreviations, unless they are very common terms in your industry.
- Test Samples Before Deployment: Always run trial text samples containing difficult English words to ensure the system responds as expected.
Explore AIVISION’s Solution
AIVISION is a Vietnamese speech AI company with experience deploying solutions for hundreds of enterprises in Vietnam and abroad, including the USA, Mexico, the Philippines, and Thailand. Our aiv-tts-S.1.0 product stands out not only for its high-quality Vietnamese voice but also for its perfect handling of English pronunciation in TTS, bringing naturalness and professionalism to every application.
We are committed to providing accurate, secure, and efficient speech technology solutions to help your business enhance user experience and optimize workflows.
Experience the difference with AIVISION’s advanced TTS technology. You can start today with a free trial to verify the voice quality and multilingual processing capabilities.
If you need further advice on integrating this technology into your existing systems, check out Pricing to learn about service packages, or Contact the AIVISION technical team for support. Explore more in-depth articles on speech technology at Blog.
Frequently asked questions
Why is pronouncing English words within Vietnamese sentences difficult for TTS systems?
Because the system must accurately identify the boundary between the two languages and adjust intonation and stress to ensure seamlessness. If handled poorly, the voice will sound choppy or mispronounced, making it difficult for users to listen to.
How does AIVISION's aiv-tts-S.1.0 model handle code-switching?
The model is trained on high-quality Vietnamese data containing interleaved English, enabling it to recognize context and pronounce English words naturally and seamlessly within Vietnamese sentences without abrupt transitions.
Does AIVISION support audio formats for call centers?
Yes, AIVISION supports standard telephony formats such as 8 kHz G.711 μ-law / A-law, suitable for deployment in call center and customer care systems.
How can I start using AIVISION's TTS service?
You can create an account and start a free trial on AIVISION's signup page. We provide a free usage limit of $5 every day for every account.
What is the voice quality of AIVISION's solution?
According to internal benchmarks, AIVISION's model achieves high accuracy, with a word error rate of 11.84%, particularly in contexts containing English terminology.
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By
Dr. Giang Vo — CEO, AIVISION
Dr. Giang Vo is the CEO of AIVISION, leading the development of s2speech — speech recognition, AI voices and a large language model for Vietnamese — and working with companies at home and abroad on their deployments.