Bad work results from voluntary co-worker

Question

I am currently working on a voluntary translation project for a game. We're working in a team of ~5 people per language (3 active translators in our case) in a Smartcat project. However, one of the translators (also, the one that does most of the translating) tends to deliver very poor quality results, i.e. bad grammar, missing punctuation etc., so that I need to go over most of his translations again to fix these errors.

My question here is: what would be the best way to communicate he might not be the best fit for the job without it coming across as insulting? And should I rather start talking to him or the project coordinator?

I know it's a voluntary job without pay and we can't expect the best quality, however it is still the official translation for the game and it's a game I care deeply about and I want the quality to be as high as possible.

Edit (I don't have enough reputation to comment yet, so I'm going to have to answer this way) : thank you for the suggestion, but as I am not in any position of authority, the answers from Politely telling an incompetent software project volunteer they are too inexperienced don't really apply to my situation.

Answer 1

You mention that this translator does the bulk of the work:

However, one of the translators (also, the one that does most of the translating) tends to deliver very poor quality results

Is it possible that his translations are suffering through simply trying to get through them too quickly? Of course quantity doesn't make up for quality, but the workload seems poorly distributed if one translator out of 3 is doing the majority of the work. Perhaps you could say something along the lines of: Hey [fellow translator], you don't need to translate x amount every day. We're not on a time crunch, so you can take your time and ensure the translation is of the best possible quality.

Or, as @Gaultheria noted, it may be that this translator is most familiar with the game's original language, and you are more familiar with the language it's being translated to. In that case you may want to set up a more formal two pass system so that he's more of a translator and you're more of an editor. That way you won't have to feel like you're picking up his slack, and it improves the quality of the translation because nothing will slip through your corrections.

Either way, it's best to address the translator directly to understand the situation and give feedback. If he responds poorly, then you can escalate to the project coordinator.

Answer 2

Why is voluntary related to quality? You would only expect incompetent people to volunteer? (Isn't the point of volunteering to provide excellent quality without the cost?)

The way to tell the person is to get them to do it. Ask the person "Please do a short self-evaluation for me. Tell me your strengths, where you want improvement, and what tasks are most appealing for you. Rate yourself 1 to ten.