Gothic was originally written in an alphabet purportedly invented by biblical scholar Wulfilas for his translation of the New Testament. It contains a compilation of latin, greek, and cyrillic-type characters, some directly borrowed from these scripts, others slightly modified. There is also a more ancient but less attested runic alphabet upon which some of the characters are based.
1 The unlikely gothic equivalent ahsa has been purported to mean 'axle' or 'ear of corn.'For the most part, gothic letters are pronounced much as their transliterated equivalents, though there are certain diphthongs and consonant clusters whose values change according to their situations.
The voiced consonants b, d, and g are generally plosive [b, d, g], though they become continuant [β, ð, γ] when occurring between two vowels. Furthermore, g may have become an unvoiced continuant [x] at the end of a word. Further still, g became nasalised when geminate or before another velar consonant; i.e. gg = ŋg, gk = ŋk, and gq = ŋkw. Click here for some more specifics and a little ranting about the pronunciation of g as well as some thoughts on the pronunciation of h.
The letter h is pronounced as [h] when initial except before a sonoroant (i.e. in hl-, hn-, or hr-). In all other cases it is pronounced as [x] (or possibly [ç]).
The letter i may be written as i or ï. In the gothic script, ï indicated an i used at the beginning of a word or syllable (and thus not part of a diphthong). It is rarely transliterated in this manner.
The sonorants l, m, n, and r may act as syllabics [l̥, m̥, n̥, r̥]¹, such as in hagl, bagms, or figgrs.
¹ In pure IPA, these would be written [l̩, m̩, n̩, r̩], but for some reason it has become the convention in germanic linguistics to use a ring beneath syllabic letters (generally used to indicate an unvoiced consonant) instead of a vertical line. Please do not be confused - they are not unvoiced.The letter x does not really exist in true gothic language. This is a borrowing of the greek χ and is used only in greek words. The letter w is often used to transliterate the greek letter υ, and as such is often transliterated into english as y. This site is not terribly interested in revisiting biblical scholarship, and as such, these two letters can safely be ignored beyond knowing that the numerical value of x is 600.
Among the vowels, curiously there is no written equivalent of short o, short e, or long i. These are written as diphthongs. (See below.)
The most complicated part of gothic pronunciation is mastery of the diphthongs/digraphs, whose pronunciation is still a hot-button issue amongst linguistic scholars. I present here the pronunciation that i've found to be most correct in my studies of the gothic language.
Please note, however, that the above system is completely artificial; Wulfilas did not distinguish between his diphthongs using diacritic markings, so the differences between the various forms of ai and au were extrapolated by later scholars, many of whom i disagree with. You may find that i tend to shy away from a lot of instances of [ai/au] in favor of [ɛ:/ɔ:] when the general concensus indicates otherwise. I believe that, for the most part, [ai/au] occur only in syllables with primary stress (háims, ráuþs) but not in many unstressed syllables where many of my colleagues would place them (habaidēdjau not habáidēdjáu, þaim not þáim). I also tend to be more conservative on the side of Proto-Germanic than many. However, there is another contingent (such as Voyles) who believe that there are no instances of [ai/au], and that all instances of ai and au are, respectively, [ɛ(:)] and [ɔ(:)]. I disagree with them as well. (I'd cite as my primary example words like náus with plural naweis or mawi with plural máujōs.)