1. Alphabet
The most obvious difference between Persian and Tajik is the alphabet that is used to write them. Persian is written in the Perso-Arabic script, while Tajik is written in the Cyrillic script. This difference is largely due to the historical influences of Iran and Tajikistan. Iran was once part of the Arab Caliphate, and so adopted the Arabic script. Tajikistan, on the other hand, was part of the Soviet Union, and so adopted the Cyrillic script.
2. Vocabulary
While Persian and Tajik share a common vocabulary, there are also some differences in the words that are used. This is due to the fact that the two languages have evolved independently over time. Some words that are commonly used in Persian may not be used in Tajik, and vice versa.
3. Pronunciation
There are also some differences in the pronunciation of Persian and Tajik. For example, the letter "q" is pronounced as a "gh" in Persian, while it is pronounced as a "k" in Tajik. The letter "z" is also pronounced differently in the two languages. In Persian, it is pronounced as a "z", while in Tajik it is pronounced as a "zh".
4. Grammar
There are also some differences in the grammar of Persian and Tajik. For example, the word order in Persian is typically Subject-Object-Verb, while in Tajik it is typically Subject-Verb-Object. Persian also has a number of verb tenses that are not found in Tajik.
5. Dialects
There are also a number of different dialects of Persian and Tajik. These dialects vary in terms of their pronunciation, vocabulary, and grammar. For example, the Persian dialect that is spoken in Iran is different from the Persian dialect that is spoken in Afghanistan. In Tajik, there are also three main dialects: Northern Tajik, Southern Tajik, and Central Tajik.
Despite these differences, Persian and Tajik are still mutually intelligible. Speakers of one language can usually understand the other language with relative ease. This is due to the fact that the two languages are so closely related.