The question behind the question is usually "will it sound like a person, or like Google Translate?" Those are very different products.
Sinhala script and Singlish are not the same thing
Most Sri Lankans do not type in Sinhala script on a phone. They type Sinhala using English letters — "mata linen shirt ekak one, kiyada?" — which is usually called Singlish. A chatbot that only understands Sinhala script will miss the majority of real messages.
A good agent answers in the same script the customer used: Sinhala script gets Sinhala script, Singlish gets Singlish. Mixing the two inside one message is the clearest sign of a weak tool.
How to judge the Sinhala in sixty seconds
- Ask it something casual and see if the reply sounds spoken or written. Literary Sinhala in a shop chat is wrong even when it is grammatically perfect.
- Type in Singlish and see whether it answers in Singlish or switches to Sinhala script.
- Look for stray characters from other Indic scripts — Devanagari or Bengali letters slipping into Sinhala text is a common failure and instantly visible.
- Check that prices use LKR or රු., never the Indian rupee symbol.
That last one sounds trivial and is not: models frequently reach for ₹ when writing South Asian languages, and quoting Indian rupees to a Sri Lankan customer undermines the whole conversation.
Why the language is the product
For a Sri Lankan shop, a bot that answers in awkward Sinhala is worse than no bot. The customer notices immediately, and it makes the business look careless. Agent Kesh chose its model by blind test: three native speakers compared real sales chats from competing models without knowing which was which, and the model with the best Sinhala won.