Etymology

Always derived from ON, cp. OIcel middle voice ǫðlask 'to win, gain as property, get for oneself', indicating an (unattested) active voice ǫðla, with which cp. the rare OE geæþelian 'ennoble, make excellent' < a PGmc wk. v. *aþalōjan- derived from the n. *aþalan (cp. OSw aðal 'nature, disposition', OHG adal 'descent, lineage'; cp. further OIcel øðli, eðli 'patrimony, origin', OE æþelu 'nobility', OS adali 'noble origin', OHG edili 'clan, nobility' < *aþaljan). The strongest evidence for ON input is semantic: although the form could (aphetically) continue the native v., the senses of the ME v. 'earn, merit, deserve' all fit better with the reflexive sense of the ON. The OE v. certainly lies behind ME iæðelien 'raise to the rank of nobility, ennoble' (attested only in LB; see MED s.v. iæðelien and OED s.v. i-athel(e)), in contrast. More circumstantially, it may be significant that the aphetic form is only cited from N/EM texts by MED and OED3.
As Bj. (159) notes, the consonant change to /d/ before /l/ here occured in ME (see further Jordan-Crook §206); cp. fiðele in LB with fydell in c1500 Corneus (Ashm 61).
 

PGmc Ancestor

*aþalōjan-

Proposed ON Etymon (OIcel representative)

ǫðlask 'to win, gain as property, get for oneself'
(ONP ǫðla (vb.))

Other Scandinavian Reflexes

Icel öðlast, Norw odla

OE Cognate

geæþelian 'ennoble, make excellent'

Phonological and morphological markers

Summary category

C3c

Attestation

First attested in Orrm, with citations exclusively from N/EM texts in ME from MED and OED3. Widely attested in MnE dial, incl. Nhp. and War., but most frequent in N (see EDD, OED3).

Occurrences in the Gersum Corpus

WA 3191

The D MS of WA reads attelland a mede at 3191 for A MS adill þaim a mede. TPD (3319n) allow that the A MS reading 'could be correct', but note that the sense 'expecting' is otherwise unrecorded for attle (v.) and argue instead that the reading in D came about as an attempt to avoid this rare v.

Bibliography

MED adlen (v.) , OED3 addle (v.1) , HTOED , EDD addle (v.2), Bj. 159, de Vries ǫðlast, Mag. öðlast, Orel *aþalōjanan,