Feet
Use this for the singular 'foot'. In Spanish, you must change the article ('el'/'los') and the noun ending to specify singular or plural.
This means 'paws' or 'legs' and is used for animals or furniture. Using 'pies' for an animal sounds strange.
My feet hurt after walking.
The baby has very small feet.
I need a shoe for my right foot.
The dog has muddy paws.
The word 'pies' for human feet is standard and understood everywhere in the Spanish-speaking world. The main difference is pronunciation.
In most of Spain, the 's' at the end of 'pies' is pronounced more softly or sometimes aspirated. Also, when using commands with 'vosotros', the form changes, e.g., 'Lavaos los pies' (Wash your feet).
While 'pies' is the standard word, you will hear the 'voseo' form in commands, such as 'Lavate los pies' instead of the 'tú' form 'Lávate los pies'.
In many parts of the Caribbean (Cuba, Puerto Rico, Dominican Republic), the final 's' in 'pies' is often aspirated or omitted in rapid speech, sounding like 'pieh'.
Using 'pies' for a single foot. For example, saying 'Me duele los pies' when only one foot hurts. — Always use the singular 'el pie' for one foot: 'Me duele el pie'.
Using 'pies' for animals. For example, 'Los pies del gato'. — Use 'patas' for animals. 'Las patas del gato' (the cat's paws). 'Pies' is reserved for humans.
Forgetting the article 'los' or 'el'. English often omits articles (e.g., 'I have big feet'), but in Spanish, you almost always need one. — Say 'Tengo los pies grandes', not 'Tengo pies grandes'.
Pronouncing 'pies' as one syllable ('pyez'). — It's a two-syllable word with the stress on the 'e'. Break it down: 'pi-ES'.