Learn Turkish: Spekülasyon yapmayan birtakım yatırımcılar bu dalgalanmadan şikâyet ediyor. - A number of investors who do not speculate complain about this fluctuation.

When birtakım is written as a single word, it functions as an indefinite adjective meaning "some" or "a number of". If it were written as two separate words (bir takım), it would literally mean "one team" or "one set/suit".

How does yapmayan connect to yatırımcılar?

Yapmayan is a subject relative clause using the -(y)An participle in its negative form. It combines yap- (do/make) + -ma (negative) + -y- (buffer) + -an (who does). Because it acts like an adjective, it sits directly in front of yatırımcılar, creating the phrase "investors who do not speculate".

Why does the sentence use the ablative case -dan in bu dalgalanmadan?

The verb şikâyet etmek (to complain) requires the thing being complained about to take the ablative case (-dAn). In Turkish grammar, you complain from a situation rather than about it.

What is the root of dalgalanma (fluctuation) and how is it built?

It comes from the noun dalga (wave). The suffix -lan turns it into the verb dalgalanmak (to ripple or fluctuate). Adding the verbal noun suffix -ma turns it back into a noun, meaning "fluctuation".