Short-vowel ‘ak1’ and long-vowel ‘aak1’ used to be the literary and colloquial readings respectively of the character 扼. Today, most dictionaries (廣州話正音字典, 廣州音字典, 廣州話發音與口語, 4 sources in CUHK site) only give the literary reading ‘ak1’ for 扼. According to academic Godfrey Liu (粵語論文集 p.32), the process has just started for all ‘aak’ sounds to be absorbed by ‘ak’. I do agree that, in the case of扼, ‘ak1’ is more popular than ‘aak1’.
UniHan gives ‘aak1’ and ‘aa1’ as variants, but this is probably based on a pre-2008 version of our CantoDict. So LSHK is the only source that has ‘aak1’ as a variant reading for 扼.
Fyi, LSHK lists 14 ‘ak1’ characters, and 3 of them (厄扼握) have variant readings of ‘aak1’. 廣州話發音與口語 (p.126) lists 6 ‘ak1’ characters, but only 2 of them have ‘aak1’ as variant. These two are 呃 and 握; 扼 has no variant.
UniHan gives ‘aak1’ and ‘aa1’ as variants, but this is probably based on a pre-2008 version of our CantoDict. So LSHK is the only source that has ‘aak1’ as a variant reading for 扼.
Fyi, LSHK lists 14 ‘ak1’ characters, and 3 of them (厄扼握) have variant readings of ‘aak1’. 廣州話發音與口語 (p.126) lists 6 ‘ak1’ characters, but only 2 of them have ‘aak1’ as variant. These two are 呃 and 握; 扼 has no variant.