The Tenctonese on Alien Nation have two alphabets, corresponding to our printed and cursive alphabets. The printed alphabet, which seems to have been first used in the episode "Gimme Gimme" (Nu-Knit), consists of separate characters, as shown in the caption above the alphabet.
The main titles for the recent made-for-TV movies, however, show the words "Alien Nation" in a connected style (distinctly different from the titles used during the show's all-too-brief lifespan as a weekly TV series). The letters are similar to (but not identical to) the printed version used elsewhere in the series.
Extrapolating from the extant characters (A, E, I, L, N, O and T), and taking advantage of the interesting characteristic that the lower half of the alphabet contains the first half rotated 180 degrees (compare M with N above, for example), here is my best guess at the cursive, or connected, alphabet (referred to in the novels as sinescript):
The W (and its counterpart, D) is taken from the billboard of "White Gold" brand sour milk. Although this billboard was apparently made for the show before an actual alphabet was developed (Tenctonese writing previous to "Gimme Gimme" appears to be merely random squiggles), the lone sigil seemed a perfect candidate to replace the symbols which would look identical when flipped (and already look very similar to the C/X and E/V characters).
The numbers, designed by Pete Chambers (president of the Alien Nation Appreciation Society) and the ampersand are shown below. Also used by the shows are the period, hyphen, comma and apostrophe characters, but as these seem to have been "borrowed" from their Terran counterparts, they are not shown here.
Although an actual language has been developed for the show, the signs and graffiti used onscreen consist of English words written in the Tenctonese alphabet. That helped immensely in allowing me to figure out the alphabet; the signs NO SMOKING and AUTHORIZED PERSONNEL ONLY printed with Tenctonese and Roman characters in juxtaposition were a veritable Rosetta stone.
The TrueType and Adobe Type I fonts available at the top of the page have mapped the "printed" alphabet to the uppercase characters (A-Z), and the "cursive" alphabet to the lowercase set (a-z). I have made both types of font available because, for some reason, the TrueType version of the font does not work under OS/2 Warp 4. The font name is JSL Tencton Round.
Thanks are due to Tim Gathercole; his independently developed font provided me with the letters J and Q, as well as the numbers.
For more information, visit the Bureau of Tenctonese Language!