Learn Portuguese (Portugal): Antes de dormir, os maus pensamentos trazem ansiedade. - Before sleeping, bad thoughts bring anxiety.

It comes from the verb pensar (to think). By adding the suffix -mento, which is a very common way to turn verbs into nouns in Portuguese, we get pensamento (thought). Words with this suffix usually represent the action or the result of the verb.

Is the -dade in ansiedade also a noun-forming suffix?

Exactly! The suffix -dade (often similar to "-ty" or "-ness" in English) is used to turn adjectives into nouns that express a state or quality. Here it gives us ansiedade (anxiety). A handy tip to remember: nouns ending in -dade are almost always feminine, which is why it is a ansiedade.

Why does the Portuguese sentence use the infinitive dormir instead of a gerund like "dormindo" for "sleeping"?

In Portuguese, whenever a verb directly follows a preposition like de (as in the phrase antes de), it must be in its infinitive (dictionary) form. While English uses the "-ing" form to say "Before sleeping", Portuguese grammar requires the equivalent of "Before to sleep".

What is the singular form of maus, and why doesn't it end in "-es" like some other plurals?