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 SEOLCAN in a-seolcan (be slothful, or sluggish). Its only satisfactory cognate is: Middle High German SELKEN (to drop, fall). 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)Andrew
 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.