I have sometimes heard people say, “Ancient Greek is the most precise language in the world.” This usually comes from people who have not studied Greek for themselves and haven’t really seen its quirks first-hand.
I don’t know how best to respond. True, there are distinctions which Greek makes that English doesn’t make, but in turn there are distinctions English makes which Greek doesn’t make. (For example, “I said” and “they said” would both be expressed εἶπον [eipon] in Ancient Greek, since the first person singular and third person plural look identical in certain tenses.) As long as the idea of overall precision is left undefined, it’s not really possible to measure whether or to what extent one language is “more precise” than another.