This paper examines the Arabic origins of question and modal words in English, German, French, Latin, Greek, Russian, and Sanskrit from a lexical root theory perspective. The data consists of 21 terms like who, what, why, when, where, which, how; can/could, will/would, shall/should, may/might. All such words, the results exhibit, have true Arabic cognates, with the same or similar forms and meanings. Their different forms, however, are all found to be due to natural and plausible causes and different courses of linguistic change. Moreover, all the wh-question words in the so-called Indo-European languages developed from one form-viz., hu-in Germanic languages (English how, German wie, Gothic hvaiwa), qu-in Romance (Latin, French, Italian quis/que), Slavic (Russian kto), Sanskrit (kah), and Greek ti (tos), to which gender, number, and case endings were added, leading to different forms and different meanings like who, what, why, how, when, where in English. All such forms descended eventually from Arabic kaifa/kai 'how' via different routes of sound change, turning /k/ into /q/ in Latin and French, /h/ in English, and /t/ in Greek while /f/ became /w (u)/ in all. That is, Arabic kaifa (kai) → (i) kwa in Latinate → (ii) haifa, haiwa/wa in Germanic → iii) ta/sa in Greek/Irish or something similar. Also the auxiliary or modal words had true Arabic cognates. Consequently, the results indicate, contrary to Comparative Method claims, that Arabic, English, and all (Indo-)European languages belong to the same language, let alone the same family. They, therefore, prove the adequacy of the lexical root theory according to which Arabic, English, German, French, Latin, and Greek are dialects of the same language with Arabic being their origin all because of its phonetic complexity and huge lexical variety and multiplicity (10 v. 1).