Looking through Richardson's (1850) vocabulary of Sokna Berber today, I came across a wonderful little piece of sociolinguistic history. The vocabulary in question was written by a Sokni, Ali ben El-Haj Abd et-Tawil, with English translations added by Richardson. He wrote, among other things, the numerals. 1-3 are Berber (əjjin اجين, sən سن, šaṛəṭ شارط), while 4 is Arabic (أربعة arb`a). But when he reached 5 there was a moment of indecision:
Do you see what's going on there? He started out by writing خمسة xəmsa, the Arabic loanword meaning "five" - which, if other languages of the region are any guide, was the usual word for "five" in everyday Sokni. But then he had a thought - xəmsa is just Arabic, it's not proper Sokni, and I ought to be giving this stranger proper Sokni - and he overwrote the word with فوس fus "hand", used by Berber and Songhay groups through much of the Sahara (eg Siwi fus=hand, Kwarandzyey kəmbi=hand) as a substitute for "five" to prevent Arabic speakers from understanding, as they would if the normal numerals, borrowed from Arabic, were used. What at first sight looks like just a piece of messy handwriting turns out to bear witness to a moment of linguistic purism.