Endings (add to end of word): -es for plurals; -ir if someone or something is doing something; -nu for words ending in -ing; -da for words ending in -ed (regular past tense); -in for the.
For numbers: For numbers like 21, 31, 41, etc., the pattern is as follows: supplementary num. + ground num.
(ex. 21 is tuvaddeinn)
This pattern applies to the hundreds, thousands, etc.,
(ex. 134 is deiðratrítityrir and 1679 is eiþúesðradesjöníde).
Ground numbers are 1-9; Secondary numbers are 10-19; Supplementary numbers are 20, 30, 40, 50, 60, 70, 80, 90