"I would like to say a few words."
Translation:Я хочу сказать несколько слов.
It depends on the context. There are polite forms in Russian that are made up of хотел бы. But when you talk to someone you know or are in another everyday situation, it is normal to use я хочу. Different to English you do not bother with the polite form in Russian sometime. I guess duolingo cannot teach you the specifics of situational use.
I was frustrated that duolingo did not accept the answer Xочу сказать несколько слов. It is known that one can leave out the personal pronoun in Russian, why is it not accepted as an answer?