Note: Do not rely on this information. It is very old.
LL. l, the twelfth letter and ninth consonant of the English and Latin alphabets, derived through the Greek lambda from the Phoenician lamed, and ultimately from the Egyptian hieroglyph of a couchant lion. It is a voiced consonant produced by placing the tip of the tongue against the upper interior gums (as in English), or against the inside of the upper teeth, and then breaking the contact after letting a slight murmur escape over the sides of the tongue. The Welsh ll is a kindred voiceless sound, a strong audible breath passing over the sides of the tongue just before the contact is broken. At the end of monosyllabic words this letter is written double after single vowels. Sometimes l before a consonant and after a modifies the a, as does final ll, except in shall, e.y. halt, salt, falter. appalling, taller, call, fall; and sometimes l in the middle of a word is silent after the broad a, as in calf, half, calm, palm. The sound in the French word mouillee, the Italian gl, is nearly English ly. The l murmur, or sonant l, is often written le in English, as in sickle, single, little, fiddle, simple, double, and unaccented al, el, often have this sound. The voiceless l murmur is heard in the French temple.