Which AI translation technology was first to implement 'zero-shot translation' - the ability to translate between language pairs it wasn't explicitly trained on?

The retail industry is increasingly adopting AI-powered language translation tools to serve global customers. These sophisticated systems have evolved dramatically in recent years, breaking down language barriers in both online and physical retail environments. Some leading technologies can now translate between hundreds of languages, offering near real-time communication for customer service, product descriptions, and even voice interactions. How well do you know the cutting edge of retail AI translation technology?

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Google's Neural Machine Translation (GNMT)
Amazon's Polly Translation System
OpenAI's Multilingual GPT
Microsoft's Z-Translator