The T in ChatGPT stands for Transformers. The similarity between the OG Transformer from 2017 and GPT3 (and other modern LLMs) is pretty big
Also, LLMs use "in-context learning" ie you actually ask it "hey, translate this" and then it has a conversation with you where you can ask to clarify or provide word definitions.
Google Translate is more hardcoded; a big problem with it is that it can't explain any of the decisions it's made or show its uncertainty about anything.
Of course, neither of these are reliable since they hallucinate.