Learn Romanian: Colegii sunt tineri. - The colleagues are young.

The first i makes the word plural (colegi means colleagues), and the second i acts as the word "the" attached to the end (colegii means the colleagues).

How do I pronounce the double 'i' in colegii?

Unlike a single -i at the end of a Romanian word, which is often just a short whispered sound, a double -ii is pronounced clearly as a full "ee" sound, like in the English word "see".

I thought sunt meant "I am". Why is it used here for "The colleagues are"?

The verb a fi (to be) is special because it uses the exact same word for "I am" (eu sunt) and "they are" (ei/ele sunt). You can tell it means "are" here because the subject is the plural noun colegii.

Why is the word for young tineri instead of tânăr?

In Romanian, adjectives must match the noun they describe. Because colegii is a masculine plural noun, the singular adjective tânăr (young) changes to its plural form, tineri.