In English we have some pretty odd spelling-to-sound correspondences, one of which is “GH” (see more here: http://www.howtospell.co.uk/gh-words). Just how far the sound can stray from spelling is illustrated with the neologism “ghoti” – pronounced like “fish” because GH can represent /f/ as in “tough,” O can represent /ɪ/ as in “women” and TI is frequently pronounced /ʃ/ as in “action” (more on ghoti and its friend ghoughpteighbteau – pronounced “potato” – here: http://en.wikipedia.org/wiki/Ghoti).
Intriguingly, many of these GH-words are cognates with German where the GH corresponds to CH:
das Recht – “right”
das Lachen – “laugh”
durch – “through”
tochter – “daughter”
acht – “eight”
As German has much more regular spelling-to-sound correspondences, there are two main options for the pronunciation of CH, namely /ç/ as in durch /dʊrç/ and /x/ as in acht [axt] (this latter spelling-sound pattern appears for some speakers of English in the Scots Gaelic word “loch”). The third possibility is to pronounce CH as /ks/ as in Achse /aksə/ which corresponds generally to the spelling X in English – die Achse is “axel” or “axis.” (Note that when there is a morphological boundary between S and CH, for example in am reichsten, reich + -sten “richest,” the /ks/ pronunciation is not used.)
There are some loan words in German where the pronunciation of CH does not follow one of these three patterns. For example, there are numerous streets in Hamburg that are called Etwas+Chausee /ʃɔˈse:/. Following the “ghoti” example, perhaps this could be spelled *Tiausee?!