Functionality
Developers
Purchasers
Translation managers
Higher level management in the translation provider
The level of proficiency may be measured, for example by local education tests, internationally recognised examination schemes or organisation-internal testing. However, in the case of the translation consumer it is probably unrealistic to imagine having more than an informal idea of target language proficiency.
In a specific evaluation, the level of proficiency in the target language of a potential or intended translation consumer will strongly influence what are considered as acceptable measures of functionality.