Many tables v/s one table with different entities types
You could really use either option: one translation table with a FIELD_TYPE partitioning attribute, or a one translation table for each table requiring localization.

The pros and cons of either approach are not likely to be related to the criteria you ask about: space or query performance.  These aren't necessarily the most important criteria for you to be concerned about either.  Unless you have really substantial scalability requirements then you should focus on code maintainability as a differentiator rather than disk space or query performance.

Another factor to consider is how much time you want to spend explaining your choices to other developers.  If you use a single table with a partitioning attribute, then you are opting for something very much like Entity Attribute Value (EAV) which is widely frowned upon for many mostly good reasons.

On the other hand, having a translation table per translatable object lets you tailor your column sizes to the actual data rather than picking the largest common denominator and also use tools like declarative referential integrity which are generally seen as best practices.