New use of "unless"?

[Laurence Horn]

At 11:10 AM -0500 1/23/01, Beverly Flanigan wrote:
>>  > 1)  Could "unless" in this context be a substitute for "lest"?
>>
>>
>>I have heard people in Central PA use "unlest" in this context.
>
>I would assume the /t/ is added as liaison with the following vowel, as in
>"acrosst", "oncet", "twicet," etc.--common in much of the Midland.
>
>But I suppose "lest" alone (re: Salovesh) is derived from "unless" too,
>which suggests the usage of both has a long history.
>
>_____________________________________________
The evidence seems to indicate otherwise.  Both "lest" and "unless"
ultimately derive from "less", but "lest" was around for four
centuries before "unless", and according to the OED the "un-" in the
latter is really a reanalysis of destressed "on".  "Lest" is attested
in 1000, "unless" in the 15th c., and unlest(e) (with three citations
from the 16th century) is given as an obsolete variant of the latter.
This would be one of many cases where the OED's "obs." should really
be "obs. and dial."  I don't think "lest" necessarily figures in
"unlest".

larry