A programme open across several countries will receive applications the review team cannot read. There are four ways to handle it, and they are not equivalent.
Require one language. The simplest, and the one with the largest hidden cost. It does not remove the translation work, it moves it to the applicant. Organisations that can afford a professionally translated proposal are usually the larger, better-resourced ones, so the requirement quietly selects for size rather than merit. If the programme exists to reach small local organisations, this option works against its own purpose.
Translate everything centrally. Defensible and expensive, and it inserts a step between submission and review that is easy to underestimate in the calendar. Worth it for a shortlist, rarely worth it for a full intake.
Recruit reviewers who read the language. Usually the right answer. A reviewer reading the original catches what a translation flattens: the register of the writing, whether the organisation knows its own community, whether the budget narrative matches the project. It also removes the delay. The constraint is finding them, which is a recruitment problem rather than a process problem, and it is solvable months before a call opens.
Machine translation. Acceptable for triage, not for the decision. It is good enough to tell you what an application is about and which reviewer should receive it. It is not good enough to judge on, and a decline based on a machine translation is not one you can defend to the applicant.
Two things to fix regardless of the route.
Publish the eligibility rules and the assessment criteria in every language the call accepts. An applicant invited to write in their own language but judged against criteria they can only read in English is being assessed on a document they never fully saw.
Keep the original. Translations are working documents; the submitted text is the record. If a decision is questioned two years later, the file has to contain what the applicant actually wrote, which is a plain audit trail requirement.
A grant management software platform runs one call in several languages at once: the form, the eligibility rules and the criteria localised, submissions stored in the language they arrived in, and routing that sends each application to a reviewer who reads it. Our note on running a programme across countries, currencies and languages covers the wider setup.