Regionalism or just bad English?

Solution 1:

I will address the substitution of seen for saw. I see no problem with the uses of away.

This is a feature of a non-standard American English spoken by many native speakers of a low socioeconomic group and by Southerners. I know this from personal experience, but found the following sources to support my assertion.

One socially marked feature is the use of nonstandard past tense and past participial verb forms, especially on irregular verbs. For example, the verb to see in standard English has the past tense saw and the past participle seen: I saw him yesterday; I’ve seen him three times this week.

Nonstandard dialects may regularize these forms by using one of several strategies. One is to form the past tense by using the regular inflection, spelled -ed, yielding a sentence like I seed him yesterday. Another is to use one form for both the past and past participle forms, yielding sentences like I seen him yesterday or I’ve saw him three times this week.

Excepted from Linguistics for Non-Linguists, by Frank Parker Kathryn Riley

Wikipedia says this is also said to be a feature of Southern American English.

Use of done (instead of did) as the past simple form of do, and similar uses of the past participle in place of the past simple, such as seen replacing saw as past simple form of see. I only done what you done told me. I seen her first.

Another Wikipedia article identifies this as a feature of Appalachian English, a subset of the low socioeconomic class.

Finally, John G. Fought's thoughts on this phenomenon.

The great American linguist Leonard Bloomfield observed many years ago that the child who learns to say I seen it has learned just as much as the one who says I saw it. Both of these forms are irregular. The least common American past-tense form of see is the regularized form I seed it. These so-called mistakes shed more light on language than “standard” forms, because what’s going on is clearly not ignorance, laziness or poor schooling. The pattern of present, past and perfect of see, seen and seen in place of see, saw and seen reveals that speakers don’t put irregular verbs together just by combining a stem and a suffix, the way they form many thousands of English regular verbs. Among the roughly 180 ‘approved’ irregular verbs now listed in grammars of American English, there is no verb with an -en suffix in the past as well as the perfect form.

So where does I seen it come from? It follows a more general pattern implicit in all the regular verbs and in many irregular ones as well. All of the regular verbs, such as need, needed,, and about 75 of the irregular ones, such as lead, led, led, have the same form in the past and present perfect, but a different form in the present. The see, seen, seen formation fits this more inclusive pattern, which can be stated as present differs from past and perfect; the past is like the perfect minus 'have.'

Solution 2:

It's probably not really people using seen instead of saw. It's eliding have into 've so much that it disappears completely. Or not hearing the muted 've in childhood, and repeating what you did hear. I don't think it's really what I'd call dialectal or regional - just uneducated/young/casual speech.

I'm not sure why OP objects to forms like I'm away to bed, or I'm away to fetch [whatever]. Sure, they're "informal". And more likely to occur in Scotland (where"Awa tae fuck wi ye!" is a common coarse dismissal). But they seem perfectly "grammatical" to me (just as with off instead of away).