Bruce Rusk, in a comment to "A bilingual, biscriptal product designation in Taiwan", mentioned "the informal Taiwanese Mandarin pronunciation of 給 ('give') gei3 as gie (3rd tone?), which is not a 'legal' Mandarin syllable" and noted that he "always assumed it was influenced by Taiwanese."
Bruce's mention of "給 ('give') gei3" in turn reminds me of a related Taiwanese-Mandarin interference that affected my own speech in a profound way.
When I was living in Taiwan from 1970-72 at an early stage of my acquisition of fluency in Mandarin, I kept hearing something that sounded to me like "oa ga li gang" in Taiwanese. It was constantly on the lips of everybody. I didn't know exactly what it meant, and I wouldn't have been able to transcribe it accurately in Romanization, much less in characters. So ubiquitous was this expression that — from the contexts in which it was spoken — I gathered that it was almost like the equivalent of "You know (what I mean)" in contemporary American English.
It wasn't long before I realized that "oa ga li gang" must have been the equivalent of "wǒ gěi nǐ jiǎng 我給你講 (I tell you)" in Taiwan Mandarin (Táiwān Guóyǔ 臺灣國語). Now, this "wǒ gěi nǐ jiǎng 我給你講 (I tell you)" was as omnipresent in Taiwan Mandarin as "oa ga li gang" was in Taiwanese. Pretty soon, "wǒ gěi nǐ jiǎng 我給你講 (I tell you)" became one of my favorite expressions in Mandarin. It's not that I consciously wanted to use it to show how good and "native" my Mandarin was, it's simply that it rubbed off on me. Everybody else was saying "wǒ gěi nǐ jiǎng 我給你講 (I tell you)", so willy-nilly I started saying it too. I also took to saying "wǒ gēn nǐ jiǎng 我跟你講", which means essentially the same thing as "wǒ gěi nǐ jiǎng 我給你講 (I tell you)" because I also heard a lot of people using that expression in Taiwan.
But after I left Taiwan in 1972 and began the more formal and academic study of Chinese, I started to feel that "wǒ gěi nǐ jiǎng 我給你講 (I tell you)" and "wǒ gēn nǐ jiǎng 我跟你講 (I tell you)" were not proper, standard Mandarin. So I tried hard to weed them out of my speech, but it probably took me twenty years to do so. I don't think I say them very often anymore, perhaps not at all.
If I wanted to say the "proper" Mandarin equivalent of "wǒ gěi nǐ jiǎng 我給你講 (I tell you)", I would probably say "wǒ gēn nǐ shuō 我跟你說" or "wǒ gàosu nǐ 我告诉你". Nevertheless, since I try to avoid such empty expressions in my speech, I don't use "wǒ gēn nǐ shuō 我跟你說" or "wǒ gàosu nǐ 我告诉你" very often either.
However, most ironically, wǒ gěi nǐ jiǎng 我給你講 ("I tell you" or "let me tell you"), has recently come back into my consciousness in an amazing way. Namely, now on the Chinese internet, you will often encounter this expression: wā gā lǐ gòng 哇嘎里共. If you try to extract any rational meaning from the surface significations of those four characters, you will get nowhere, for they are being used strictly to roughly transcribe in Mandarin these four syllables of Taiwanese: góa kap lí kóng. That, my dear friends, is none other than the Taiwanese pronunciation of wǒ gěi nǐ jiǎng 我給你講 ("I tell you" or "let me tell you").
So we've come full circle. What all of this demonstrates, I believe, is that the persistence of language is a powerful force, something that is difficult for governments to suppress. While Taiwanese and Cantonese, for example, may seem to be threatened by the policies of the Communist Party of the People's Republic of China and the Nationalist Party of the Republic of China, both Taiwanese and Cantonese are having a large impact on the way language is used in Taiwan and on the mainland, I tell you.
[Thanks to Grace Wu and Melvin Lee]