----------------------------------------
|context> => |context: learning plurals>

source |context: learning plurals> => |url: http://www.macmillandictionary.com/thesaurus-category/british/irregular-plurals>

plural |word: *> #=> merge-labels(|_self> + |s>)

plural |word: calf> => |word: calves>
plural |word: child> => |word: children>
plural |word: corpus> => |word: corpora>
plural |word: elf> => |word: elves>
plural |word: foot> => |word: feet>
plural |word: goose> => |word: geese>
plural |word: genus> => |word: genera>
plural |word: half> => |word: halves>
plural |word: hoof> => |word: hooves>
plural |word: index> => |word: indices>
plural |word: knife> => |word: knives>
plural |word: leaf> => |word: leaves>
plural |word: life> => |word: lives>
plural |word: loaf> => |word: loaves>
plural |word: matrix> => |word: matrices>
plural |word: medium> => |word: media>
plural |word: man> => |word: men>
plural |word: mouse> => |word: mice>
plural |word: ovum> => |word: ova>
plural |word: ox> => |word: oxen>
plural |word: penny> => |word: pence>
plural |word: person> => |word: people>
plural |word: quantum> => |word: quanta>
plural |word: radius> => |word: radii>
plural |word: scarf> => |word: scarves>
plural |word: self> => |word: selves>
plural |word: serum> => |word: sera>
plural |word: sheaf> => |word: sheaves>
plural |word: shelf> => |word: shelves>
plural |word: sky> => |word: skies>
plural |word: stratum> => |word: strata>
plural |word: tooth> => |word: teeth>
plural |word: testis> => |word: testes>
plural |word: this> => |word: these>
plural |word: that> => |word: those>
plural |word: wife> => |word: wives>
plural |word: wolf> => |word: wolves>
plural |word: woman> => |word: women>
----------------------------------------