According to Berowa and Flores (2020) the most inconsistently distributed vowel is the low-front unrounded /ӕ/ that has a tendency to be realized as low-central unrounded /a/. This particular phonological situation has been noted by all previous studies of Philippine English phonology (Llamzon, 1969; Gonzalez & Alberca, 1978; Tayao, 2004; Regala-Flores, 2014; Jubilado, 2016).
Several word pairs in Philippine English tended to realize the low-front unrounded /æ/ as low-central unrounded /a/ in words like "land," "map," and "tank," which were heard as [land], [map], and [taŋk]. This tendency to use /a/ for /ӕ/ has been identified as a significant phenomenon in the phonology of Philippine English, commonly observed in a variety of new English varieties. At the same time, it was noted that this pronunciation pattern deviates from the older features observed by Llamzon in 1969 that are specific to the SFE variety.
/ɔ/ and /o/
In terms of producing the long, tense back vowels /ɔ/, these were observed to present in the speech of most pairs of speakers, specifically when saying words such as "all," "bought," "saw," "longer," "for" and "call." This finding aligns with previous research by Llamzon (1969), who reported a similar feature in his study of SFE, as well as with the acrolectal features discussed by Llamzon (1997) and by Tayao (2004). The present study confirms the inclusion of the open vowel /ɔ/ in the sound inventory of Philippine English, even though it contradicts Tayao's (2004) statement that Filipinos typically substitute this sound with other sounds from their native language. It is possible that the emergence of the use of the open vowel /ɔ/ as a feature is due to it being present in the words produced during the reading and spontaneous speaking tasks. Speakers may have heard these words daily, especially from the mass media or English teachers. Moreover, the Filipinos are known to have an extraordinary ear and an impressive ability to mimic, which they may have used to pick up on the correct pronunciation of words (Gonzalez & Alberca, 1978). The same explanation may also be true in relation to the production of mid-back rounded /o/. The use of simple and familiar words such as boat [bot], poll [pol], promoting [prəmotɪŋ], nobody [nobadi], and mango [mӕŋgo] may have facilitated the preservation of vowel /o/ sound in various verbal tasks.