"Mi wnaeth e weld llygoden."
Translation:He saw a mouse.
mi and fe are used in some dialects as a 'positive pre-verbal particle' - something which indicates that the following verb is a positive statement and not a question or a negative. Mi is very common in north-west Wales and we do include it sometimes on this course. Fe is used more in south and south-west Wales, but it is less common nowadays. In this usage, they no longer mean I/me/he/him as they once did in earlier forms of the language.
If they are used, they cause soft mutation of the verb that they are being used with . The soft mutation sometimes remains in the colloquial language even if they are not there, as in the common forms Ges i..., Gaeth..., Wnes i...., etc.
As with any dialect forms, unless you live in or regularly visit an area where they are used, keep things simple and don't use them yourself. You need to be aware that they exist, though, as some of them they regularly come up in the written and spoken media.
The standard course for adults in the South uses 'Gwelais i' for South Wales and 'Mi wnes i weld' for North Wales. These are the forms we started with.
We're happy to add other valid forms but it takes time so if you flag (report) any instances where 'fe' forms would be appropriate then we'll happily add them.