Why are there two classes of synonyms of "di" in Google Translate?

Question

When you look up the Italian word "di" in Google Translate, you get the following screen:

To the right, there are some English translations of the word, and each English translation has again some Italian translations, which can be regarded as (more or less) synonyms of "di".

On the left side, there are some other words which are labelled as synonyms. However, the word "di" on the left side is understood in a way that's a bit more special than that on the right side: It's the word "di" in "buon di" (meaning "day"), and the second person imperative of "dire" (e.g. "dimmi!"). So we get "giornata" and "significare" as synonyms.

Is there a specific reason why Google Translate shows these synonyms in this way? When I think of synonyms of "di", the words on the right side would come to my mind before those on the left side. But those on the left side are marked as "synonyms", and those on the right side not.

Answer 1

Prepositions in different languages don't correspond one-to-one.

For instance, the French de can be the Italian di or da; the English by can be the Italian da, but also per or in: I'll come by train translates to verrò in treno; but I'll come by foot becomes verrò a piedi.

The prepositions di, a, per and in are definitely not synonyms; the page you link to simply shows a list to choose the appropriate preposition from. In the same way, of, to, for, in and so on are not synonyms in English.

Learning a language in the form “the Italian preposition di translates into English of when…, to when…” is a sure way to become thoroughly confused.

Answer 2

Words on the right side are not synonyms of "di", they are other possible translations of the given word in English. For instance, Google Translate is saying that English preposition "of" can sometimes be translated as "di", but in other situations it can also be translated as "a", "in", "per" or "da parte di" (it's really hard to see if this is true without a specific context). I wouldn't say that "di" and "a" or that "di" and "in", which are pairs of different Italian prepositions, are synonyms.