* Extensive borrowing: Persian adopted thousands of Arabic words, especially in areas like religion, philosophy, science, and administration. These words are deeply integrated into the Persian vocabulary.
* Differing grammar and structure: Persian and Arabic have distinct grammatical structures, even if they share some similar sounds. While some Arabic words are used directly in Persian, others are adapted and modified to fit the Persian grammar.
* Evolution of languages: Both Persian and Arabic have evolved over centuries, meaning borrowed words have changed in pronunciation, meaning, and usage. It's difficult to quantify the exact influence of Arabic on Persian's evolution.
Therefore, a percentage figure for Arabic influence on Persian is not accurate or meaningful. It's more accurate to say that Persian has been significantly influenced by Arabic, particularly in its vocabulary. This influence is reflected in the rich and complex tapestry of the Persian language.