Etnaachar اتناشر

The Coptic Engine: In Coptic grammar, compound numbers from 11 to 19 are built by taking the number 10—which is Ⲙⲏⲧ / Ⲙⲉⲧ (Mēt or Met)—and gluing the single digit directly to its tail. The Coptic word for 12 is written as Ⲙⲉⲧⲥⲛⲁⲩ (Met-snau) or Ⲙⲉⲧⲥⲛ̄ⲧⲉ (Met-snte), meaning "Ten-Two". [1]

The Clash with Arabic: In MSA, 12 is written as two completely separate, un-glued words: Ithna 'Ashar (اثنا عشر). It requires a massive vocal layout: you must pronounce Ithna, break your breath, and then pronounce the heavy pharyngeal 'Ayn (ع) and Sheen (ش) of 'Ashar.

The Egyptian Twist: The Egyptian tongue found the multi-word Arabic layout completely unnatural because their native Coptic engine demanded that compound numbers be fused into a single, seamless breathing block.

1. They took the modified base Et- (from etnén).
2. They dropped the heavy Arabic 'Ayn (ع) sound entirely from the word 'Ashar.
3. They smashed the two words together into a single, fluid compound word, turning -achor into a sleek, suffix-like tail: ـناشر (-nachar).
4. This created إتناشر (etnachar). The syntax is a direct mirror of Ⲙⲉⲧⲥⲛⲁⲩ—a single, un-broken, fused compound token.