Editing Interlingue (section)

==== Derivation ====
[[File:Occidental derivation.png|thumb|An example of derivation from the magazine Cosmoglotta.]]
[[File:De_Wahl's_Rule.png|thumb|Flowchart demonstrating derivation of nouns from verbs using de Wahl's rule.]]
The application of [[de Wahl's rule]] to verbs, and the usage of numerous suffixes and prefixes, was created to resolve irregularities that had plagued creators of language projects before Occidental, who were forced to make the choice between regularity and unnatural forms, or irregularity and natural forms. The prevailing view before its application was that natural forms needed to be sacrificed for the sake of regularity, while those that opted for naturalism were forced to admit numerous irregularities when doing so ([[Idiom Neutral]] for example had a list of 81 verbs with special radicals<ref>{{Cite web|url=http://anno.onb.ac.at/cgi-content/anno-plus?aid=e0m&datum=1948&size=45&page=45|title=Cosmoglotta B, 1948, p. 45|access-date=20 January 2019|archive-date=15 April 2021|archive-url=https://web.archive.org/web/20210415020143/https://anno.onb.ac.at/cgi-content/anno-plus?aid=e0m&datum=1948&size=45&page=45|url-status=live}}</ref> used when forming derivatives), a paradox summed up by [[Louis Couturat]] in 1903 as follows:<ref>{{Cite book|url=https://archive.org/details/histoiredelalang00coutuoft/page/472/mode/2up|title=Histoire de la langue universelle|last1=Couturat|first1=Louis|last2=Leau|first2=Léopold|date=1903|publisher=Paris Hachette|others=Robarts – University of Toronto|quote=Translation: "En somme, on se trouvait acculé à cette antinomie : les mots internationaux ne sont pas réguliers, et les mots réguliers ne sont pas internationaux; l'opinion dominante était qu'il fallait sacrifier la régularité à l'internationalité dans la formation des mots. Julius Lott concluait qu'on ne peut pas éviter les irrégularités des langues naturelles, et VON Wahl, qu'on ne peut pas donner à la L. I. plus de simplicité et de régularité que n'en comportent nos langues."}}</ref>

<blockquote>In short, one finds oneself confronted by the antinomy that the words that are international are not regular, and the words that are regular are not international; the prevailing opinion [of naturalists such as Julius Lott and de Wahl] was that regularity should be sacrificed for internationality in the formation of words.</blockquote>

The rules created by de Wahl to resolve this were first described in 1909<ref>{{Cite web|url=https://sites.google.com/site/latinosineflexio/-1909-13-discussiones-api#1909:21|title=Abstracti Verbal-Substantives – Edgar de Wahl (Discussiones de Academia pro Interlingua, Nov. 1909: 21–5)|access-date=19 December 2020|archive-date=18 August 2016|archive-url=https://web.archive.org/web/20160818041229/https://sites.google.com/site/latinosineflexio/-1909-13-discussiones-api#1909:21|url-status=live}}</ref> in the ''Discussiones'' of Peano's Academia pro Interlingua and are as follows:

#If, after the removal of '''-r''' or '''-er''' of the infinitive, the root ends in a vowel, the final -t is added. Crear (to create), crea/t-, crea/t/or, crea/t/ion, crea/t/iv, crea/t/ura.
#If the root ends in consonants d or r, they are changed into s: decid/er (to decide), deci/s-, deci/s/ion deci/s/iv. Adherer (to adhere), adhe/s-, adhe/s/ion
#In all other cases, with six exceptions, the removal of the ending gives the exact root: duct/er, duct-, duct/ion.

Once these rules were applied, Occidental was left with six exceptions. They are:<ref>{{Cite web|url=https://anno.onb.ac.at/cgi-content/anno-plus?aid=e0g&datum=1929&page=197&size=45|title=Cosmoglotta A, 1929, p. 193|access-date=6 March 2021|archive-date=13 April 2021|archive-url=https://web.archive.org/web/20210413203409/https://anno.onb.ac.at/cgi-content/anno-plus?aid=e0g&datum=1929&page=197&size=45|url-status=live}}</ref>

#ced/er, cess- (concession)
#sed/er, sess- (session)
#mov/er, mot- (motion)
#ten/er, tent- (temptation)
#vert/er, vers- (version)
#veni/r, vent- (advent)

Suffixes are added either to the verbal root or the present theme of the verb (the infinitive minus -r). An example of the latter is the suffix -ment: move/r, move/ment (not movetment), experi/r, experi/ment (not experitment), and -ntie (English -nce): tolera/r (tolerate), tolera/ntie, existe/r (exist), existe/ntie.<ref>{{Cite web|url=https://anno.onb.ac.at/cgi-content/anno-plus?aid=e0g&datum=1929&page=197&size=45|title=Cosmoglotta A, 1929, p. 192|access-date=6 March 2021|archive-date=13 April 2021|archive-url=https://web.archive.org/web/20210413203409/https://anno.onb.ac.at/cgi-content/anno-plus?aid=e0g&datum=1929&page=197&size=45|url-status=live}}</ref>