bob wrote:In German it's common to use word combinations like cable tv (kabelfernsehen) or computer screen (computerbildschirm). These words are written as one word.
In English it's seems to be common to split these words (cable tv, computer screen). Is this a general rule? When do I have to split and when not? Does it depend on the word?
There is no clear rule about this. It depends on usage and the evolution of the language. In your examples, cable and tv are nouns used as adjectives. In English, such expressions often enter the language as two discrete words, and then evolve through a hyphenated stage to a single-word stage. The evolution is often faster in US English.
For example, recent editions of the Concise Oxford Dictionary give both house husband
whereas Webster's (US) gives househusband
. Both dictionaries give the somewhat older word housewife
The fusion of two words in this way is more frequent when they are short words.
In the future you may very well see cable-tv
seems unlikely but not impossible) or computerscreen
The German-speaking peoples seem more readily adaptable than the English-speaking peoples.