, c- , s- , respectively). The finals -ing and -eng have largely merged into -in and -en , respectively. Taiwan Guoyu Taiwan Guoyu pronunciation is strongly influenced by Minnanyu. This is especially prominent in areas where Minnanyu is common, namely, in Central and Southern Taiwan. Many, though not all, of the phonological differences between Taiwan Guoyu and Putonghua can be attributed to the influence of Minnanyu. Notable phonological features of Taiwan Guoyu include: Utterances in Taiwan Guoyu may feature retroflexes (in pinyin, zh-, ch-, sh-, and r-) realized as postalveolar consonants: to , to , to , and to . This phenomenon is not unique to Taiwan, and can be found Mandarin dialects across southern China as well as parts of north China. The ability to produce retroflex sounds is considered a hallmark of "good" Mandarin (i.e. Standard Guoyu); some speakers may hypercorrect to pronounce alveolar consonants as their retroflex counterparts when attempting to speak "proper" Guoyu. The initial f- becomes a voiceless bilabial fricative , closer to a light 'h' in standard English (for example, fǎn → huǎn). The syllable written as eng () after labials (in pinyin, b-, f-, m-, p- and w-) is pronounced ong (). Thus, fēng may be pronounced as fōng. The semivowel may change, rendering e.g. the surname Wēng as rather than . The deletion of also happens in colloquial Putonghua, but less frequently. The initials n- and l- are sometimes interchangeable, particularly preceding nasal finals (i.e. -n, -ng). Thus, nán may be pronounced lán. The nasal finals -n and -ng tend to merge, so words like zhēng and zhēn may become homophones. The endings -uo, -ou, and -e (when it represents a close-mid back unrounded vowel like in hē) shift to a mid central vowel or merge into the mid back rounded vowel -o . The close front rounded vowel in words such as yǔ become unrounded, transforming into yǐ. The diphthong -ei and the triphthong -ui are monophthongized into . Reduction The non-standard Taiwanese Guoyu tends to exhibit frequent, informal elision and cluster reduction when spoken. For example, zhè yàngzi 'this way, like so' can be pronounced similar to jiàngzi 'paste, sauce'; wherein the "theoretical" retroflex (so called because it is a feature of Standard Guoyu but rarely realized in everyday speech, as zh- is usually pronounced z-; see above section) is assimilated into the palatal glide . Often the reduction