"Tell me" but not "tell to me" / "Explain to me

Hi, Tim,

Unfortunately there is no rule that can give non-native speakers a clue. You just have to learn verbs AND structures - that's the only way to know how they operate.
The reason for the different way we use verbs is calld VALENCY. It shows how words (in our case verbs) combine with other words.

TELL can take two objects (a direct and an indirect one) and allows the so-called dative movement transformation, i.e. the shift of the indirect object to a position before the direct object with deletion of "to":
EX.: She told the truth (direct object) to him (indirect object). OR She told him the truth. (In the case of TELL, the latter is more common.)

GIVE is of the same valency category as TELL. Therefore:
EX.: She gave the book to him. OR She gave him the book.

EXPLAIN, however, follows another pattern - it does not allow the dative movement transformation. So your sentence "Please explain me the difference" is incorrect. You can only say "Please explain the difference to me."

Other categories require a specific preposition, an infinitive (with or without "to"), an -ing form etc. There are a total of 19 different patterns!

Hope that helps!

It is "nearly a rule" that the monosyllabic verbs take "me" and the polysyllabic verbs take "to me", at least in the majority of the verb classes illustrated.

And in any case the mention of who gets the explanation is much less common in English than in many other languages. It's perfectly idiomatic to say, "Could you please explain how to do this?" You don't have to say, "Could you please explain to me how to do this?" In fact, the second version is less idiomatic.

CJ