I don't know how to link these to other languages. IMO 'bouder', the pl and ru links should be available.
Sulk is from Old English SOLCEN (sulky, languid), past participle; from SĒOLCAN in a-seolcan (be slothful, or sluggish). Its only satisfactory akin lexeme is: Middle High German SELKEN (to drop, fall), but this is not necessarily Germanic. Hence it was just as well removed from the main Entry, since its meaning does not connect with that of SĒOLCAN above. Not connected with Spanish HOLGAR (to be lazy), unless of Iberian origin; in which case no Proto-Indo-European root could be applied; but because of the Middle High German connection, a P.I.E. root could be *SĒhL2Gh. Andrew H. Gray 17:40, 8 September 2015 (UTC)
 means 'Absolutely not;  means 'Exceedingly unlikely';  means 'Very dubious';  means 'Questionable';  means 'Possible';  means 'Probable';  means 'Likely';  means 'Most Likely' or *Unattested;  means 'Attested';  means 'Obvious' - only used for close matches within the same language or dialect, at linkable periods. '2' inserted in root words stands for a larygeal to represent an 'a' that does not exist.