Since you asked Gail, it is not possible to spell Manx in the Manks language as both the letters x and z are wanting in the Manks phonology.
To really bore you to death here is an extract from Cregeen's Dictionary of 1835.

THE alphabet consists of seventeen single and three double consonants, and seven vowels - a, e, i o, u, w, y. Of the consonants, fifteen are mutable - b, c, ch, d, f, g, j, k, m, p, q, s, sh, sl, t. The immutables are - l, n, r, which always retain their sound; and alter not, except when preceded by s in the beginning of a word to show the degrees of comparison. gh and ph begin no radical, or at least ought to begin none, as the language now stands.