English is perfectly suitable, since most of the technical literature, describing how to build and maintain everything around you is in English. German and Span

English is perfectly suitable, since most of the technical literature, describing how to build and maintain everything around you is in English. German and Spanish are also fine. There are fields, where German prevails (funny enough, one of them is oriental linguistics). English is lingua franca of science and technology and there is no alternative to that. This is cultural domination consequence everyone is facing.