Orcs dislike dirty-blood orcs, and will be shunned and exiled. Therefore half-orcs tend to grow up in human or other racial company, and hold deep grudges towards true-bloods, but will equally suffer from dislike and distrust from human groups. Dwarves, elves and hobbits, who will also have experienced racial opinions are more likely to be considerate of a half-orc.
Players Handbook (page 17)
Orcs are fecund and create many cross-breeds, most of the offspring of such being typically orcish. However, some one-tenth of orc-human mongrels ore sufficiently non-orcish to pass for human. Complete details of orcs and crossbreeds will be found under the heading Orc in ADVANCED DUNGEONS & DRAGONS, MONSTER MANUAL.
House Rule
Half-orcs like all other races do not have infravision or seeing in the dark!
Languages
Half-Orcs can speak common orcish (but just their dialect) and common tongue. They can understand other dialects, but only speak in their local dialect.
And, wait for it, only those with intelligence of 16 or more, can speak 1 other language, and as always, the character has to have a logical reason for knowing the additional language.
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