Learn Italian: Scarico un'app per imparare le lingue. - I download an app to learn languages.

You can attach the instrumental ci (meaning 'with it' in this case) directly to the end of the infinitive verb by dropping the final -e. So, 'to learn with it' becomes impararci. The full sentence would be: Scarico un'app per impararci le lingue.

Why does un'app have an apostrophe? Is the word feminine?

Yes, app is treated as feminine in Italian because it is short for applicazione, which is a feminine noun. Because of this, it takes the feminine indefinite article una. Since app starts with a vowel, una drops its final letter and takes an apostrophe, becoming un'.

Why do we need per before imparare? Doesn't the infinitive already mean 'to learn'?

While the English infinitive often includes 'to', in this sentence 'to learn' specifically means 'in order to learn' (it shows the purpose of downloading the app). In Italian, you must use per plus the infinitive verb to express 'in order to'. Without per, the sentence would fall apart grammatically.

The verb scaricare means 'to download'. Does it have other common meanings?