"They are not warm."

Translation: Ele nu sunt calde.

[ArguingInElvish]

How come I cannot use "Ei nu sunt calde" ?

[potestasity]

Adjectives usually vary with the gender of what they characterize. It should be "Ei nu sunt calzi"

[ArguingInElvish]

What am I confusing? Aren't Ei and Ele both forms of They?

[potestasity]

They are, but even things in plural have genders and so some adjectives have 4 forms: cald - caldă - calzi - calde (masc. sg. - fem. sg. - masc. pl. - fem. pl.). "Ele" is used for a group of all feminine stuff and adjectives describing it must be in their feminine plural form. "Ei" is used for groups with at least one masculine member and adjectives have to be in their masculine plural form.

[Pop60]

Just to confirm that Ei nu sunt calzi is accepted so either Ele or Ei will work SO LONG AS THE ADJECTIVE MATCHES THE GENDER