Ll

In English, ll represents the same sound as single l: /l/. The doubling is used to indicate that the preceding vowel is (historically) short, or for etymological reasons, in latinisms (coming from a gemination).

In Spanish, ll was considered a digraph from 1754 to 2010 as the fourteenth letter of the Spanish alphabet because of its representation of a palatal lateral articulation consonant phoneme (as defined by the Royal Academy of the Spanish Language).

In official Galician spelling the ll combination stands for the phoneme /ʎ/ (palatal lateral approximant, a palatal counterpart of /l/).

In Catalan, ll represents the phoneme /ʎ/. For example, as in llengua "language" or "tongue", enllaç "linkage", "connection" or coltell "knife". In order to not confuse ll /ʎ/ with a geminated l /ll/, the ligature ŀl is used with the second meaning. For example, exceŀlent is the Catalan word for "excellent", from Latin excellente. In Catalan, l·l must occupy two spaces, so the interpunct is placed in the narrow space between the two L: ĿL and ŀl. However, it is more common to write L·L and l·l, occupying three spaces; this practice is not correct although it is tolerated.L.L and l.l are incorrect and not accepted. See interpunct for more information.

...
Wikipedia