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AI voices: text-to-speech, voice cloning and the ethical boundaries

An explanation of text-to-speech and voice cloning technology, how to choose a tool for Vietnamese, and the rules on consent, transparency and preventing fraud.

Edited by PickYourToolUpdated: 2026-10-265 min read

AI voices are now natural enough to use for explainer videos, audiobooks, trial podcasts, call centers and lectures. The same technology can clone a person's voice from a short recording, and can be abused for fraud. This article explains both sides: how to use it effectively and the boundaries you should keep.

Three different capabilities

Text-to-speech (TTS). You provide text, pick a ready-made voice, and the tool reads it. Suited to narration, lectures and accessible content for visually impaired people.

Voice cloning. From a person's recording sample, the tool creates a simulated voice. It is lawful and useful when the owner consents, for example when you clone your own voice to narrate many videos.

Speech-to-speech and multilingual dubbing. Keeps the speaker's voice quality but changes the language or style. Useful when translating videos into other languages.

There is also a group of supporting tools: noise removal, volume balancing, separating voice from music, and speech recognition for creating subtitles.

Choosing a tool for Vietnamese

Vietnamese has six tones and many words with different meanings depending on the diacritic, so quality can vary a lot between tools and between voices. When testing, do not just listen to the provider's sample sentences. Use a passage of your own that includes:

• proper names, place names and English loanwords;
• numbers, dates and currency units;
• long sentences, questions and exclamations;
• abbreviations commonly used in your field.

Listen with headphones, not only through speakers. Note mispronunciations, wrong emphasis and odd pauses. Many tools let you adjust the phonetic spelling or add pause marks to fix errors; that ability deserves weight in your choice.

A workflow for quality voiceover

1. Write for the ear, not the eye. Short sentences, few parentheses, numbers spelled out as words where needed.
2. Split into sections. Generate short passages one at a time so they are easy to fix, rather than the whole piece at once.
3. Adjust the rhythm. Add pauses and emphasize keywords, as the tool supports.
4. Listen to the whole thing again and mark errors.
5. Post-production. Balance the volume, remove noise, and add background music quieter than the voice.
6. Check the licenses of the voice and the background music for commercial use.

Ethical and legal boundaries

Clone a voice only with clear consent

Have a document stating who gives permission, for what purpose, for how long, and whether it may be shared. Many providers ask users to confirm that they have rights to the uploaded voice, and some have a verification step. Do not use the voice of a celebrity, colleague or relative who has not agreed.

Be transparent with listeners

If listeners could believe a real person is speaking (a call center, a voicemail, an advertisement), let them know it is a synthetic voice. The EU AI Act has provisions requiring disclosure when realistic audio content is created or edited by AI; many platforms have similar rules.

Do not use it for fraud or impersonation

Consumer protection agencies have warned about the trick of imitating a relative's voice to ask for emergency money. If you build products or content, absolutely avoid uses that mislead about identity.

Be careful with sensitive content

An AI voice reading medical, financial or legal content may feel more trustworthy than it really is. Make sure the content is accurate and cite your sources.

Protecting yourself against voice impersonation

• Agree with family or colleagues on a secret question or a spoken password for emergencies.
• When you receive a call asking for an urgent money transfer, hang up and call back on a number you already know.
• Limit posting long, clear voice recordings in public places if you do not need to.
• Do not authenticate important transactions by voice alone.
• Businesses should have a two-step confirmation process for transfer orders.

Using AI voices to increase accessibility

A very positive use: turning articles into audio for visually impaired people or people who find reading difficult, making subtitles and translations for deaf people, and creating multilingual lectures. When you do this, pay attention to pronunciation quality and let users speed up or slow down playback.

Cost and limits

Pricing is usually by the number of characters or minutes. High-quality voices, voice cloning and commercial rights are usually on paid plans. Estimate the number of characters per month, including regenerations. See how to read AI tool pricing.

Combining with video

AI voices often go with video as narration. See the full workflow in the article on making videos with AI.

Conclusion

A voice is part of a person's identity. Using this technology to save time and increase accessibility is reasonable, as long as you have consent, are transparent with listeners and avoid every form of impersonation. If you are not sure whether a use is acceptable, ask yourself: would the owner of this voice agree if they knew exactly what was happening?

This article is general reference only and does not replace legal or professional advice. See also the editorial, affiliate and review policy.