قال ابن خلدون في كتابه المقدمة
It 1328 should be known that all languages are habits similar to crafts (techniques). They are habits (located) in the tongue and serve the purpose of expressing ideas. The good or inadequate (character of such expression) depends on the perfection or deficiency of the habit. This does not apply to individual words but to word combinations. A speaker who possesses a perfect (linguistic) habit and is thus able to combine individual words so as to express the ideas he wants to express, and who is able to observe the form of composition that makes his speech conform to the requirements of the situation, is as well qualified as is (humanly) possible to convey to the listener what he wants to convey. This is what is meant by eloquence.
Habits result only from repeated action. 1329 An action is done first (once). Thus, it contributes an attribute to the essence. With repetition it becomes a condition, which is an attribute that is not firmly established. After more repetition it becomes a habit, that is, a firmly established attribute.
As long as the habit of the Arabic language existed among the Arabs, an Arab speaker always heard the people of his generation (race) speak (Arabic). He hears their ways of address and how they express what they want to express. He is like a child hearing individual words employed in their proper meanings. 1330 He learns them first.1331 Afterwards, he hears word combinations and learns them likewise. He hears something new each moment from every speaker, 1331a and his own practice is constantly repeated, until (use of proper speech) becomes a habit and a firmly established attribute.
Thus, (the child) becomes like one of (the Arabs). In this way, (Arab) languages and dialects have passed from generation to generation, and both non-Arabs and children have learned them. 1332
This is (what is) meant by the common saying: "The Arabs have (their) language from nature." 1333 That is, they have it from (their own) original habit, and while (others) learned it from them, they themselves did not learn it from anyone else.
The (linguistic) habit of the Mudar became corrupt when they came into contact with non-Arabs. The reason for that corruption was that the generation growing up heard other ways of expressing the things they wanted to express than the Arab (ways). They used them to express what they wanted to express, because there were so many non-Arabs coming into contact with the Arabs. They also heard the ways in which the Arabs expressed themselves. As a result, matters became confused for them. They adopted (ways of expressing themselves) from both sides. Thus, there originated a new habit which was inferior to the first one. This is what is meant by "corruption of the Arabic language." 1334
Therefore, the dialect of the Quraysh was the most correct and purest Arabic dialect, because the Quraysh were on all sides far removed from the lands of the non-Arabs. Next came (the tribes) around the Quraysh, the Thaqif, the Hudhayl, the Khuza'ah, the Banu Kinanah, the Ghatafan, the Banu Asad, and the Banu Tamim. The Rabi'ah, the Lakhm, the Judham, the Ghassan, the Iyad, the Quda'ah, and the Arabs of the Yemen lived farther away from the Quraysh, and were (variously) neighbors of the Persians, the Byzantines, and the Abyssinians. Because they had contact with non-Arabs, their linguistic habit was not perfect. The Arabic dialects were used by Arab philologists as arguments for (linguistic) soundness or corruption according to the (degree of) remoteness of (the tribes speaking them) from the Quraysh.
And God knows better.
المصدر:
http://www.muslimphilosophy.com/ik/Muqaddimah/Chapter6/Ch_6_45.htm
