Erik helped me with this final solution: TypoScript template > setup ->
config.linkVars = L
config.sys_language_uid = 0
config.language = pt
config.locale_all = pt_PT.utf8
config.metaCharset = utf-8
[globalVar = GP:L = 1]
config.sys_language_uid = 1
config.language = en
config.locale_all = en_GB.utf8
[global]
Erik, thank you!