I don't think perfect universal translation will never be possible, much less in real-time.
Consider for example how many languages aren't subject-verb-object word order like English. Klingon, for example: https://en.wikipedia.org/wiki/Klingon_language#Grammar
Or if in the same conversation you need to refer to "LOL" the textspeak phrase and "L.O.L." the acronym for some company. And the person you're speaking to doesn't use the English/Latin alphabet.
Or if two languages don't have the same number of terms or number of usages for certain things. For example both "He is a soldier." and "It is a soldier." in English translate to "Es un soldado." in Spanish. Suppose that there are multiple subjects in the conversation, making "he" or "it" relevant. Or what if you're translating to a language that doesn't have grammatical gender? And what if you try to account for formal/familiar etiquette which differs between languages?