Germanic and Semitic languages have been established as two different and basically unrelated language families. This indeed explains the strong basic differences that are found between them. As a speaker of English, German and Arabic, I always notice some strange similarities in certain words from these three languages. When I look for the root of the English and German words in Proto-Germanic dictionaries, the similarity to Arabic becomes even more visible. However I do not find explanations or suggestions in the literature for these similarities. So here I list some of the words I noticed. I would be happy if you could indicate literature or share your thoughts about this.
English / German / Proto-Germanic / Arabic
Egg / Ei / Ajja / ojja (=egg)
Field / Feld / Fela / felaha (=agriculture)
House / Haus / Hus / housh (=house)
Garden / Garten / Garda / garda (=garden)
Ship / Schiffen / ? / sufun (=ship)
Build / Bauen / Bwajan / bina (=construction)
Caesar / Kaiser / Kaisar / kaisar (=strong)
Cave / Käfig / Kafa / kahf (=cave)
Seven / Sieben / Sebun / sebun (=seven)
Harm / Harm / Harma / haram (=harm, forbidden)
Source for Proto-Germanic : Gerhard Köbler, Germanisches Wörterbuch 1980, 2. A. 1982