MDBG says that the pinyin for 听 is tīng.

Wikipedia says that -ing is realized as [iŋ].

However, the speaker in my flash cards pronounced 听 as [tʰjəŋ]. She glided through a schwa before pronouncing the final.

I thought this might have just been a mistake, so I looked it up in MDBG, but the speaker also glides though a schwa when pronouncing tīng (interestingly, she doesn't glide though a schwa before pronouncing tìng).

Wanting more data, I checked Forvo, which offers four pronunciations from different speakers. Three of the speakers, who were from China, pronounced it how I expected: [tʰiŋ]. One speaker was from Taiwan, and he pronounced it [tʰjəŋ].

So then I though it might be a dialectical thing. But the Phonology section of the Wikipedia page on Taiwanese Mandarin had no mention of vowel changes like this.

Why do some speakers do this?

MDBG says that the pinyin for 听 is tīng.

Wikipedia says that -ing is realized as [iŋ].

However, the speaker in my flash cards pronounced 听 as [tʰjəŋ]. She glided through a schwa before pronouncing the final.

I thought this might have just been a mistake, so I looked it up in MDBG, but the speaker also glides though a schwa when pronouncing tīng (interestingly, she doesn't glide though a schwa before pronouncing tìng).

Wanting more data, I checked Forvo, which offers four pronunciations from different speakers. Three of the speakers, who were from China, pronounced it how I expected: [tʰiŋ]. One speaker was from Taiwan, and he pronounced it [tʰjəŋ].

So then I thought it might be a dialectical thing. But the Phonology section of the Wikipedia page on Taiwanese Mandarin had no mention of vowel changes like this.

Why do some speakers do this?