For the duration, you understand the literal meaning of any spoken language that you hear. You also understand any written language that you see, but you must be touching the surface on which the words are written. It takes about 1 minute to read one page of text. This spell doesn't decode secret messages in a text or a glyph, such as an arcane sigil, that isn't part of a written language.
Ritual. This spell can be cast as a ritual. The ritual version takes 10 minutes longer to cast and expends no spell slot, so it cannot be cast at a higher level; it requires a feature that grants ritual casting.
RollQuest ships the D&D 2014 SRD as a content pack, on a 5e character sheet that does the maths - roll from the sheet and let the numbers work themselves out. Free to start.