Google today brought SmartReply, its AI technology that suggests responses to messages, to YouTube. From within YouTube Studio, creators can now use SmartReply to respond to users who comment on their videos in English and Spanish. SmartReply will only make suggestions when it’s “likely to be useful,” Google says.

“[SmartReply for YouTube] helps creators engage more easily with their viewers,” Google Research scientist Rami Al-Rfou wrote in a blog post. “This model learns comment and reply representation through a computationally efficient [AI model], and represents the first cross-lingual and character byte-based SmartReply.”

Google says this latest SmartReply launch, which follows rollouts in the (now-defunct) Inbox, Gmail, Android Messages, Android Wear, and the Play Developer Console, required significant retooling. In comparison with emails, for example, which tend to be long and dominated by formal language, YouTube comments contain examples of language switching, abbreviated words, slang, inconsistent punctuation usage, and emoji.

The initial release of SmartReply for Inbox encoded input emails word-by-word with an AI system called a recurrent neural network before decoding potential replies with another word-level network. Despite the expressivity of this approach, it was computationally expensive, according to Google. For the YouTube-tailored SmartReply, engineers at the company found the same ends could be achieved with a system that searches through a predefined list of suggestions for the most appropriate response.

Rather than train a separate AI model for each language, Google opted to devise a single cross-lingual model for all supported languages. That allowed the support of mixed-language usage in the comments and enabled the model to leverage the learning of common elements in one language for understanding another, such as emoji and numbers. Moreover, having a single model simplified the logistics of maintenance and updates. While the model has been made available for English and Spanish, the flexibility inherent in this approach will allow it to be expanded to additional languages in the future, Google says.

“YouTube is a global product with a diverse user base that generates heterogeneous content. Consequently, it is important that we continuously improve comments for this global audience, and SmartReply represents a strong step in this direction,” Al-Rfou continued. “Ideally, suggestions would only be displayed when it is likely that the creator would reply to the comment and when the model has a high chance of providing a sensible and specific response.”

Coinciding with the debut of SmartReply for YouTube, Google this week reportedly began rolling out an updated version of Smart Compose, an AI-powered feature that suggests words that might follow what you’ve typed, to Gboard in beta. It previously only supported Android Messages, but now appears to work with Telegram, WhatsApp, and Google Messages.