Thank you very much!
Among many other things, ZC has been written with the global community in mind. To first address the language, there is a languages directory that would need to be populated with each language in which the site is to be displayed. The version of ZC offered from this site includes English (though it typically comes with the british flag the text is more in American English than it is in British English. For example the use of the word color instead of colour.)
If you look through the plugins area you can or should be able to download a language pack for the desired language. If the language pack is available only up to a certain ZC version and even if it matches your current version the language files should be reviewed to validate that all defined language constants are present so that applicable text is displayed rather than the constant itself.
This sounds like it would be quite easily be done.
Then there is the issue of currency which is a little less involved but the currency conversion rate does need to be at least periodically updated.
It has to be done manually, I assume. So just replace the old conversion rate with the updated / newest conversion rate daily or so in the back end.
As to modifying the site to operate differently based on the location from which the customer is accessing the site or which language they have chosen, either is possible and mostly a factor of which is considered appropriate for the method to be used. For example a foreigner in a country may want to use a familiar language but may be using a currency within that country and shipping things to yet another location.
Yes, indeed, realizing that appears to be complicated. May be the best option is just to go by the country into the ware is send to, I do not know at all.
As for shipping (and payment) there are zones that apply to each and this may require cloning a module so that the desired options are made available based on origin/destination. For example I believe I recently saw someone describe a payment method that is considered to only be available to people that live in a specific area. Therefore it should not be made available to someone that chooses a payment address outside of that location.
Sounds quite complicated either.
Could / should I first set up Zen Cart with a special, single language and after, when the set up of the shop is done completely (with that single language) start involving the (next) language or all of the languages at once? May be that is more circumstantial than implementing all of the languages / conditions for the rights (of the other countries) at the beginning instead of starting all over again. So what is the easier / better manner? Actually I would prefer to first have the shop running with one language and then add the next one / ones together.
Many thanks for the links.
Zen Cart 1.5.4 German version