I don't necessarily recommend using every tip described below. Some of them can easily result in comical characters. If you are only trying to lower your intelligence by a little bit, you may only need to follow one or two of these steps. Also, note that Half Ogres and Half Orcs do not necessarily have to be bad at puzzles, games, or reading "bad guys," but complex plots, plans, or speeches may typically overwhelm them.
Limit Your Vocabulary
Choose a set of words (perhaps 200-500, depending on how dumb you want to be, down from the normal 2,000) to which you will limit yourself.
Limit yourself to simple words - one and two syllable words for the most part, though I would recommend "happiness" over "bliss." If you need to say anything more complicated, combine two words - tree killer instead of woodcutter, for example.
Limit Tense Usage
I recommend using at most two or three tenses, and using them in an overly consistent manner.
Limit yourself to simple present tense phrases. For example, say "I fight" instead of "I am fighting."
With past tense it is important to be consistent about how you conjugate verbs. Don't say "We fought the dragon." Instead, say "We fighted the dragon" or even "We fighted da big scaly." If that feels too dumb, use "did," and say "We did fight the dragon."
Future tense is easy. You can be consistent, and always preface future tense with "will" or "gonna." I recommend choosing the helper verb ahead of time, though, and sticking with it.
- Conditional - "We maybe gonna fight the dragon" instead of "We might fight the dragon." "We maybe did fight the dragon" or "We maybe fighted the dragon" instead of "We might have fought the dragon."
- Infinitive - Use the present tense form of the word, or always prefix it with "to," even if this is inappropriate. "We prepare to fight the dragon." In general, I recommend against using complex phrases that entail using Infinitive forms of the verb, though.
- Perfect and Progressive Tenses - Avoid them.
Don't worry about it. Mix and mingle these, if you want; always speak as though you're using singular third person (or some other tense), or always get it wrong. It's an honest mistake!
Abuse First Person
Avoid the word "I." You can say "Me go to market" or "Trorg buy a big sandwich." Alternatively, use the word "I" but use verbs as though it were third person. "I goes to market. I buys a big sandwich." Or do both.
Ignore Proper Sentence Structure
Instead of saying "To whom does this sword belong?" say "Whose this sword?" (or "Who dis sword?")
Role-play getting bored when other people talk too much. Interrupt people, assuming you have understood what they're intent is. Jump to assumptions. Wander off while they're talking.
Political correctness is for the elves.
Certain words make sense to be slurred when playing one of the dumber races. "This" is typically pronounced as "Dis." Other words - or names - are just too complicated for you to understand. Instead of calling the elven lady "Aeraelastia," call her "Arlasta."
Make Decisions Differently
The rules of logic were created by a philosopher, and you are anything but. A Half-Orc or Half-Ogre shouldn't be swayed by logical arguments, but rather should utilize your own sort of decision making criteria. For example, attack a farmer who's yelling at his wife because "he yelled so he must be bad!"
Find something interesting that motivates your character
This can add depth to any character, but it can make stupid characters particularly memorable. I had a character who enjoyed making sculptures out of mud. Alternatively, just get excited about simple things (likely with some theme, still).
It's possible the character you're playing is immature rather than (or in addition to being) stupid. If so, display some of the following signs of immaturity:
- Volatile emotions - be impatient, anger easily, etc
- Dependence or COMPLETE independence - Asking someone else to always do something for you, or more likely, refusing to let anyone else do anything for you, even if they are clearly better qualified. "Nope, Trorg talk to diplormat himself!"
- Require instant gratification
- Be selfish
It's pretty difficult to be subtle. If someone tries to say something indirectly, one of the following behaviors may be appropriate:
- Be incapable of understanding
- Require multiple hints before you understand
- Require to have been told ahead of time that "I'm tired" means "Attack the people we're talking to!"
- Always assume that the cue means the same thing, even coming from other people
- Interpret other social cues incorrectly