I am not sure if I need a basic or wildcard certificate and how many.
1) I assume 1 certificate goes in 1 server - so if I have 2 web servers then i need 2 certificates?
2) From what I read wildcard is only needed for subdomains. But what about if i have the same main domain but just use subdomains for multilanguage? like my site is say www.xxx.com and when someone is viewing it in british english i change it to: uk-eng.xxx.com
In the above case will a basic certificate work or is this a wildcard?
Two web servers usually have different host names (if it's not a cluster). So you need protect both host names.
An HTTP certificate protects the host name, so a certificate for "www.xxx.com" is only for this domain. Wildcard allows subdomains, i.e. "*.xxx.com" allows all names e.g. "www.xxx.com" and "uk-eng.xxx.com", but more expencive, however you can use the same certificate on several servers.