Learn Turkish: İki taraf da konuşuyor.

In Turkish, whenever you use a number before a noun, the noun stays in its singular form. You never add the plural ending -lar or -ler if there is a number attached. So it is always iki taraf (literally "two side").

How does iki taraf da translate to "both sides"? Doesn't da mean "also" or "too"?

Exactly! The word da normally means "also" or "too". However, when you use iki (two), a noun, and then da (or de), it translates as "both" of those things. So iki taraf da literally means "two side also", which is the standard Turkish way of saying "both sides".

Why is it da and not de here?

The separate word da follows A-type vowel harmony. You look at the last vowel of the word right before it. Since the last vowel in taraf is a (a back vowel), we use da. If the last vowel had been a front vowel like e or i, it would be de.

Since "both sides" means multiple people, why is the verb konuşuyor singular instead of the plural konuşuyorlar?