The spelling of /ʧ/ is always either <ch> or <tch>. The /ʤ/ sound can be spelled <j>, <ge> or <dge>.
These two affricates are distinguished only by voicing, and can give rise to confusions occasionally among native speakers, especially when syllable-final. The danger of confusion is increased when one or both of these sounds are absent from the first language, so this is known a problem area for speakers of Dutch, German, French, Spanish, Chinese and Thai.
The absolute number of pairs is fairly small, tentative evidence in support of the O'Connor conjecture that language corrects itself when confusions are likely, and in some cases the meaning difference is so small as to suggest sounds in free variation, as in chaw/jaw, hotchpotch/hodgepodge or splotch/splodge. However, the discrimination problem becomes acute in the case of cheer/jeer, where the meanings are opposite though the contexts are very similar.
Interesting pairs include
The mean density value is 3.3%. The list makes 48 semantic distinctions, a loading of 46%.
batch badge batches badges beseech besiege beseeches besieges beseeching besieging catch cadge catches cadges catching cadging catcher cadger catchers cadgers chain Jane char jar charring jarring charred jarred chars jars Chard jarred Chas jazz chaw jaw chawed jawed chawing jawing chaws jaws cheer jeer cheered jeered cheering jeering cheers jeers cheese G's cherry jerry cherries jerries chess Jess chest jest chests jests chested jested chesting jesting Chester jester chew Jew chews Jews Chilean Gillian chill gill chills gills chin djinn chins djinns chin gin chins gins chink jink chinks jinks chip gyp chipped gypped chipping gypping chips gyps chive jive chives jives choice Joyce choke joke choked joked chokes jokes choking joking choker joker chokers jokers chore jaw chores jaws chug jug chugged jugged chugging jugging chugs jugs chump jump chumps jumps chunk junk chunks junks chunky junkie cinch singe etch edge etches edges etched edged etching edging etchings edgings H age H's ages hatches Hadjis hotchpotch hodgepodge larch large leach liege leaches lieges lecher ledger lechers ledgers leech liege leeches lieges lunch lunge lunches lunges lunching lunging lunched lunged march marge match Madge perch purge perches purges perching purging perched purged retch Reg rich ridge riches ridges search serge search surge searches surges searching surging splotch splodge splotches splodges wretch Reg
John Higgins, Shaftesbury, February 2010.