Learn Spanish (Spain): Los dedos del niño son pequeños.

In Spanish, when the word de (of) is followed by the masculine word for 'the', which is el, they always combine to form the contraction del. You will never write de el as separate words.

Why does the sentence say Los dedos del niño instead of using an apostrophe like 'El niño's dedos'?

Spanish does not use an apostrophe-s ('s) to show possession. Instead, you must always use the word order 'the [object] of the [owner]'. So, 'the boy's fingers' becomes los dedos del niño (literally, the fingers of the boy).

Why do we use son instead of están for 'are'?

We use son (from the verb ser) because we are describing a physical characteristic. The verb estar is used for temporary states or locations, while ser is used for descriptions and more permanent traits.

Why does the word for small end in '-os' (pequeños)?

In Spanish, describing words (adjectives) must match the noun they describe in both gender and number. Since dedos (fingers) is masculine and plural, the adjective must also be masculine and plural, giving us pequeños.