Irregularities and exceptions in Interlingua

Required

• The sequence "de le" is replaced by "del".
• The sequence "a le" is replaced by "al".
• If noun ends with a consonant, it takes plural in -es (instead of -s).
• If noun ends with 'c', it takes plural in -hes (instead of -s or -es).
• Not all adverbs are derived from adjectives.
• If adjective ends with -c, adverb derived from it takes -amente (instead of -mente).
• If verb ends with -ir, present particle replaces it with -iente (instead of -inte).
• If verb ends with -er, past particle replaces it with -ite (instead of -ete).
• If c is preceded by e i or y, it is pronounced as s or ts (instead of k).
• "th" is pronounced as t.
• "ph" is pronounced as f.

Optional

• "sia" as subjunctive of "esse" (instead of "esse")
• "es" as present tense of "esse" (instead of "esse")
• "ha" as present tense of "haber" (instead of "haber")
• "va" as present tense of "vader" (instead of "vader")
• "son" as plural present tense of "esse" (instead of "esse")

External links

• http://members.optus.net/~ado_hall/interlingua/gi/home/entry_page.html
• http://www.interlingua.com/en/gramword.htm