Currently our policy is that the first person willing to translate CiviCRM into a given language creates a Transifex team and becomes the team coordinator; future translators need to be approved by the coordinator.
This makes it possible to guard from spammers and keep a given localisation coherent (e.g. with regards to how different terms, like ‘househould’, should be translated), but it also means that new translators who are not quickly accepted (or denied) by the team coordinator are in limbo and wait for the decision.
Thus we should periodically check whether new translators for existing teams are handled pronto and are not discouraged/blocked when the team coordinator is inactive (or on a leave, etc.); we should poke the coordinators, elect additional ones or, in the worst cases, accept the new translators ourselves.