red dots

Evidence

"Frequent vowel signs are marked with red dots: fatha with a dot above and kasra with a dot below."

Remarks

The red dots denote vocalization: fatha (dot above), kasra (dot below), and damma (dot in the middle). Tanwin fatha is rendered by two red dots above, kasra by two below, and tanwin damma by two behind the letter (p. 149). This system is characteristic of the 9th-century Mespotamian scribal tradition.