If your first sentence is “ I would like to have some more chocolate, please.” In English, the Japanese translation would be もっとチョコレートが食べたい。僕is the subject mainly used by a male. The second sentence would be わからない言葉が、たくさんある。

Hi! - The first sentence needs some correction. If you mean "I want to eat some more chocolate please" or "I would like to have some more chocolate please" --> (もっとチョコレートが食べたいです) or (もっとチョコレートが食べたい). - The second sentence is correct in an informal use of language. But formally in grammar, it's written as: わからない言葉がたくさんある。