How are Persian, Dari, and Tajik related?

Persian, Dari, and Tajik are all members of the Iranian branch of the Indo-Iranian language family and share a close linguistic relationship.12

• Persian (Farsi): As the national language of Iran, it serves as the primary standard for this group. It developed from Middle Persian and Parthian and has been a literary language since the 9th century CE.32
• Dari: This is recognized as the Afghan dialect of Persian. While its syntax is very similar to Farsi, it features differences in its vowel system, additional consonants, and a less prominent stress accent. It serves as an official language in Afghanistan.41
• Tajik: Another West Iranian language, Tajik is the national language of Tajikistan. It is very closely related to Persian and is readily intelligible to Persian speakers, though it is considered more archaic in certain respects.2

While these languages are distinct, they are deeply connected through their shared history and linguistic roots, with Persian acting as a significant influence on the others.32