One of the problems with English spelling is the number of borrowings there have been from other languages. It is often said that English should follow the lead of languages like Spanish, that spell as they are pronounced. Leaving aside the fact that this is not strictly true of Spanish in any case, English adopts a different policy to borrowings. Spanish tends, where possible, to adapt the spelling of foreign words to Spanish orthographic conventions. Football, for instance, is borrowed as “fútbol”. This allows an approximation to the English pronunciation to be represented and copied.
English does the opposite: the original spelling is maintained (when the source language uses the Roman alphabet), with the result that English readers are expected either to know the spelling conventions of all these languages, or to ignore them and develop new pronunciations based on the English interpretation of the letters used.
In practice, of course, we get a mishmash. People use what they think is the appropriate letter-to-sound correspondence, and more often than not, get it “wrong”. Take the sequence -au- in words borrowed from German. The electrical goods manufacturer Braun is generally pronounced as /brɔːn/, taking no notice at all of the German convention for -au-. On the other hand, the beer, Löwenbräu, is pronounced /ˈləʊənbraʊ/. Perversely, here the -au- is pronounced as it would be in German if there were no umlaut above it, so while many people probably think they are being quite clever, because they ‘know’ that -au- is pronounced /aʊ/ in German, they are still “wrong”.
Similarly, the Italian product bruschetta is most often heard as /brʊˈʃetə/, because people think they know that -sch- is pronounced /ʃ/ in foreign words. They would do better to think of it in the normal English way of school, scheme, etc (and increasingly schedule in Britain as well as America).
The letter “z” is a particular problem: the prefix “schizo-” is itself fairly schizoid. Here the sch- is ‘correctly’ pronounced as in Greek, but the -z- is given a German (or Italian – but in this word German) pronunciation /ts/. The same ‘wrong’ foreign interpretation is put on the -z- in words such as chorizo (Spanish, and so originally either /θ/ or /s/), and the style of curry called dopiaza /dɒpiˈætsə/. The last two are presumably based on memories of the Italian pronunciation of -z- rather than the German.
Chorizo demonstrates -ch- pronounced as it is in both Spanish and English, but the adjective macho is often heard as /ˈmækəʊ/. Is this because it is assumed to be originally pronounced /x/ as in German or Scots, a sound not in the inventory of ‘English’ English, and replaced by /k/?
Any revision of English spelling would have to find a solution to these problems. Perhaps using the Spanish way, giving us Brown, Lervenbroy, skizofreenia, broosketta, choreetho and matcho for the words discussed above.