Until the 1980s the Kuomintang administration heavily promoted the use of Standard Mandarin and discouraged the use of Hokkien and other vernaculars, even portraying them as inferior. Mandarin was the only sanctioned Chinese variety for use in the media. This produced a backlash in the 1990s. Although some supporters of Taiwan independence tend to be opposed to standard Mandarin in favor of Hokkien, efforts to replace standard Mandarin either with Hokkien or with a multi-lingual standard have not been successful. Today, Mandarin is taught by immersion starting in elementary school. After the second grade, the entire educational system is in Mandarin, except for local language classes that have been taught for a few hours each week starting in the mid-1990s.
Taiwanese Mandarin (as with Singlish and many other situations of a diglossia) is spoken at different levels according to the social class and situation of the speakers. Formal occasions call for the acrolectal level of Guoyu (Standard Mandarin). Less formal situations often result in the basilect form, which has more uniquely Hokkien features. Bilingual speakers often code-switch between Mandarin and Hokkien, sometimes in the same sentence.
Mandarin is spoken fluently by almost the entire Taiwanese population, except for some elderly people who were educated under Japanese rule. In the capital Taipei, where there is a high concentration of Mainlanders whose native variety is not Hokkien, Mandarin is used in greater frequency and fluency than other parts of Taiwan.
There are two categories of pronunciation differences. The first is of characters that have an official pronunciation that differs from Putonghua, primarily in the form of differences in tone, rather than in vowels or consonants. The second is more general, with differences being unofficial and arising through Taiwanese Hokkien influence on Guoyu.
Isochrony is considerably more syllable-timed than in other Mandarin dialects (including Putonghua), which are stress-timed. Consequently, the "neutral tone" (輕聲) does not occur as often.
The syllable written as pinyin: eng after b, f, m, p and w is pronounced as [oŋ].
In basilectal Taiwanese Mandarin, sounds that do not occur in Hokkien are replaced by sounds from Hokkien. These variations from Standard Mandarin are similar to the variations of Mandarin spoken in southern China. Using the Hanyu Pinyin system, the following sound changes take place (going from Putonghua to Taiwanese Mandarin followed with an example):
Complete replacement of retroflex sounds (zh, ch, sh, r) by alveolar consonants (z, c, s, l). r may also become [z].
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For non-recurring events, the construction involving 有 is used where the sentence final particle 了 would normally be applied to denote perfect. For instance, Taiwanese Mandarin more commonly uses "你有看醫生嗎？" to mean "Have you seen a doctor?" whereas Putonghua uses "你看醫生了嗎？". This is due to the influence of Hokkien grammar, which uses 有ū in a similar fashion. For recurring or certain events however, both Taiwanese and Mainland Mandarin use the latter, as in "你吃飯了嗎？", meaning "Have you eaten?"
Another example of Hokkien grammar's influence on Taiwanese Mandarin is the use of 會 as "to be" verbs before adjectives, in addition to the usual meanings "would" or "will". For instance:
Taiwanese Mandarin: 你會冷嗎? (lit. "you are cold INT?")
Taiwanese Mandarin: 我會冷 (lit. "I am cold.")
Taiwanese Mandarin: 我不會冷 (lit. "I not am cold.")
This reflects Hokkien syntax, as shown below:
Hokkien: 你會寒𣍐? (lit. "you are cold, not?")
Hokkien: 我會寒 (lit. "I am cold.")
Hokkien: 我𣍐寒 (lit. "I not cold.")
In Putonghua, sentences would more likely be rendered as follows:
Putonghua: 你冷不冷? (lit. "you cold, not cold?"), or 你冷嗎? (lit. "you cold INT?").
Vocabulary differences can be divided into several categories – particles, different usage of the same term, loan words, technological words, idioms, and words specific to living in Taiwan. Because of the limited transfer of information between mainland China and Taiwan after the Chinese civil war, many items that were invented after this split have different names in Guoyu and Putonghua. Additionally, many terms were adopted from Japanese both as a result of its close proximity (Okinawa) as well as Taiwan's status as a Japanese territory in the first half of the 20th century.
Some terms have different meanings in Taiwan and China, which can sometimes lead to misunderstandings between speakers of different sides of the Taiwan Strait. Often there are alternative, unambiguous terms which can be understood by both sides.
Meaning in Taiwan
Meaning in China
to carry out something insidious, to have sex (vulgar/slang)
to do, to perform a task
As such, it is a verb that is rarely seen in any official or formal setting in Taiwan, whereas it is widely used in China even by its top officials in official settings.
The word 弄 (nòng) can be used inoffensively in place of 搞 in both Taiwan and China to convey the action "to do; to perform a task" as 弄 is widely used in both places and does not carry the vulgar connotation.
Loan words may differ largely between Putonghua and Taiwanese Mandarin, as different characters or methods may be chosen for transliteration (phonetical or semantical), even the number of characters may differ. For example, U.S. President Barack Obama's surname is called 奥巴馬Àobāmǎ in Putonghua and 歐巴馬 or 歐巴瑪Ōubāmǎ in Guoyu. Also, in Taiwanese Mandarin, rhotacization (erhua) is generally avoided.
The terms "阿公agōng" and "阿媽amà" are more commonly heard than the standard Mandarin terms 爺爺yéye (paternal grandfather), 外公wàigōng (maternal grandfather), 奶奶nǎinai (paternal grandmother) and 外婆wàipó (maternal grandmother).
Some local foods usually are referred to using their Hokkien names. These include:
弁当 in Japanese was borrowed from a Classical Chinese term using different characters but reintroduced to Taiwan via Mandarin as 便當 via different characters via 便 instead of 弁 because 便 means "convenient" which certainly is what a bento box is. In China, they used the semantic approach.