Words like molto (very/a lot), poco (little/not very), tanto (so much/many), and troppo (too/too much) can act as either adverbs or adjectives.
Modifying adjectives (Invariable)
When these words modify an adjective (telling you how expensive or cold something is), they act as adverbs. Italian adverbs never change their endings. Even if the adjective changes to match a noun, words like molto, poco, and troppo stay exactly the same (ending in -o).
| This hotel is too expensive. | Questo albergo è troppo caro. |
| The water is too cold. | L'acqua è troppo fredda. |
Notice that fredda changes to match the feminine noun l'acqua, but troppo remains unchanged.
| The teacher is not very nice. | L'insegnante è poco simpatico. |
| The people are very happy. | La gente è molto felice. |
The word abbastanza (enough, quite) also belongs in this group and is always invariable.
| The food here is quite good. | Il cibo qui è abbastanza buono. |
Modifying nouns (Variable)
When these same words describe a noun (telling you how much or how many of a thing there is), they act as adjectives. Just like regular adjectives, they change their endings (-o, -a, -i, -e) to agree with the gender and number of the noun they describe.
| There are too many people here. | La gente qui è troppa. |
| This is too much money. | Questi sono troppi soldi. |
| This is a lot of food. | Questo è tanto cibo. |
| There are many words, but time is short. | Le parole sono tante, ma il tempo è poco. |
