Learn Turkish: Yeni sezon bölümlerini ayda bir yayımlayacaklar. - They will broadcast the new season's episodes once a month.

It follows the standard Turkish pattern for expressing regular intervals: Time period + locative case (-da/-de) + bir. Here, ay (month) takes the locative -da, followed by bir (one). It literally translates to "in the month, one". You can apply this to other periods, like haftada bir (once a week) or iki yılda bir (once every two years).

Let's break down the suffixes on bölümlerini. Why are there two -i endings?

The word breaks down as bölüm-ler-i-n-i. The first -i is the third-person possessive suffix, which links the episodes to the new season (yeni sezon bölümleri meaning "new season's episodes"). Because this entire noun phrase is the direct object of the verb, we must add the specific accusative case marker. Since the word already ends in a vowel (the possessive -i), we add the buffer consonant -n- and then the accusative suffix -i.

I usually see the word for broadcast or publish spelled as yayınlamak. Is yayımlayacaklar with an 'm' a typo?

It is not a typo. According to standard Turkish grammar rules, yayım (with an 'm') is the act of publishing or broadcasting, making the verb yayımlamak. Yayın (with an 'n') is the noun for the broadcast or publication itself. In everyday use, many native speakers treat them as interchangeable and use yayınlamak as a verb too, but yayımlamak is technically correct here.