Letters that make register language
s, a, e, g, l, n, r, t, i, u are letters that make 'register language'
Words within register language
ER, LAN, language, age, gist, AN, re, la, te, register, Ag, ANG, ng, Gi, GU, GI, egis, LA, Re, NGU, Er, Ge, La, Te are words within 'register language'