First I will give the system used in An International Language (1928) and Novial Lexike (1930), which form the basis of the language.
Novial is written using the following letters and combinations of letters: a, b, ch, d, e, f, g, h, i, j, k, l, m, n, o, p, qu, r, s, sh, t, u, v, x, y.
All sounds in Novial should be enunciated clearly and cleanly.
The vowels are a, e, i, o and u. They are pronounced, more or less, as the vowels in the words "aha", "met", "see", "port", and "soon". The most important thing is that they are not slurred, or diphthongized, or reduced, but always pronounced fully and as pure vowels.
The consonants b, d, k, l, m, n, p, t, v, y are pronounced essentially as they are in English. However, note that f is always as in "for" (never as in "of"), g is always as in "go" (never as in "gem"), and h is always sounded, never silent as in "hour". Attention must be paid to the following:
Stress: The basic rule is: stress the vowel before the last consonant. However, consonantal flexional endings (ie. -d, -m, -n, -s) do not count for this (eg. "bOni" but "bOnim", not "bonIm"; "apErta" but "apErtad", not "apertAd") so perhaps it is better to say that the vowel before the final consonant of the stem takes the stress.
Later in the 1930's, Jerpersen allowed the use of two different spelling systems. The older method, described above, was known as "Fonetik Novial", or "FN"; the newer method was called "Orthographic Novial", or "ON". In this Jespersen attempted to adopt a more "naturalistic" and "historical" form of spelling, in other words to make Novial look more like both a "natural" language and its (succeeding) competitor, Occidental. The letter c was reintroduced, apparently with the pronunciation [s] before e or i, and [k] elsewhere. There were, in fact, five ways of writing the [s] sound, or rather five spellings all of which had to be pronounced [s]: s, c and sc (before e and i, as in "civil", "scientie"), as well as ç and z. The letter z was used in words such as "zone", where most source languages had a "z"; the letter ç was used when the [s] sound, represented by the letter c before e or i, was needed before an a, o or u, as in "nuançosi" from "nuance", or "prinça" from "prince". In addition, the letter y was used both as a consonant and a vowel (as in "symbole"); when used as a vowel it was pronounced the same as the letter i. Judging by the name, the combinations ph and th were also reinstated, presumably with the values [f] and [t]. In addition to this, the rule of stress was slightly amended, so that words ending in -ee, such as "kafee" (where the first e is part of the root) were to be pronounced "kafEe" (not "kAfee").