No OC version posted. However, the alternative way to install language packs would be from FTP and on the database but would simply take longer to accomplish the same goal and the only reason on using the alternative way, backup included, would be when encountering errors from the OC admin which, normally, the language pack author would need to be contacted to resolved this issue.
The most generated errors being found on Opencart forum originates from contributed programming. The increased post counters are caused by redundancies of the same solutions that were already provided prior.
Programmer / Opencart Tester