"The journalist writes."
Translation:Scríobhann an t-iriseoir.
Vowels aren't masculine or feminine, but rather broad and slender. The broad vowels are a, o, and u, and the slender vowels are e and i.
There is a rule, which a few words don't follow but most do, that any consonant or group of consonants must have either both broad vowels to the left and right of it in the word, or both slender vowels. Some compound words, like breithla, birthday, don't follow it -- notice there is an 'i' (slender) to the left of the 'thl', and an 'a' (broad) to the right of it -- and there are a few other exceptions.
Knowing this is a fantastic help in spelling. It can be hard to spell verbs correctly because some of the endings sound the same. But, as an example, if you want to spell 'I see', and you know it starts with 'feic' so it is either 'feicim' or 'feicaim', you can figure out that it has to be the first one because the 'c' must have a slender vowel to it's right since it has a slender vowel to its left. And other words besides verbs follow the same rule.
I'm not sure how you got that from khmanuel's post. Many words have both broad and slender vowels - for examples, the Irish for "word" is focal which has two broad vowels, but the plural "words" is focail which has both broad and slender vowels. bó, with a broad vowel is feminine. rí with a sender vowel is masculine.
Verbs are neither masculine or feminine. Adjectives agree with the gender of the noun that they are an attribute of.