The 24 "Taijigong" forms are all found somewhere in the hand form, so I wouldn't say that they are necessary to learn the martial art. They are a nice shortcut, however, IME.
The sequence of the Wu style hand form is essentially the same as that found in Yang style, the only major structural difference is at the end, with "High Pat on Horse" as form 105, "Grasp Bird's Tail" as 106 and then "Single Whip" as form 107 followed by the "Conclusion" as form 108. Some of the 24 forms are standing postures, "post standing" is one way to refer to them, without external movement. Others are active, moving, but without stepping. There are four internal/external conditions that describe them, and they are divided about 25% each: Stillness Inside/Stillness Outside (Horse stances and other "post standing" exercises such as "Golden Cock"), Stillness Inside/Movement Outside (which is how the form is described, incidentally), Movement Inside/Stillness outside (leading the energy through different patterns coordinated with the breathing) and Movement Inside/Movement Outside (sometimes involving "Silk Reeling" energy). The number 24 is reached, I believe, by expressing the 8 power generations (p'eng, lu, chi, etc.) in 3 circles; vertical, horizontal and diagonal.
As to which dialect the Wu family use, it depends on the family member. Wu Ta-hsin uses Mandarin for formal occasions and Cantonese with his students and quite good English (sparingly) with us. Sifu Eddie uses English, a lot, but also Cantonese with Cantonese speakers and Mandarin with Mandarin speakers. He also has passable Italian and Manchu skills. Their romanization scheme is purely phonetic, they seem to take no heed of pinyin, Yale, Wade-Giles, Mandarin or Cantonese when they romanize. T'ai Chi Ch'uan is romanized "Tai Chi Chuan" or "Tai Kik Kune" in HK. They will always romanize "Wu" as Wu, even when the rest of the name is romanized with a Cantonese pronunciation, Wu Ta-hsin …Ç´óÐÂ as Wu Tai Sin, for example. They will use "Ng" (the Cantonese pronunciation of Wu) for personal reasons, drivers licences, etc., but for business it is always Wu. Myself, I tend to use Wade-Giles (it's what I grew up using), but I truly find neither that or pinyin satisfactory ("Q" for Ch?). I find that I am starting to use pinyin more here as a courtesy to you guys, but the whole situation will be an unsatisfactory mess until I learn to read and write Chinese.
[This message has been edited by Polaris (edited 06-06-2004).]