Lexicon
Grammar
Rules (CFG)
Parser
“The dog eats the bone.”
Words
Word Category
Grammar Rules
The –
det (determiner)
dog –
noun
eats – eat - verb (morphology)
the –
det
bone noun
NP  det noun
VP  verb
VP  verb NP
S  NP VP
(NP  noun phrase)
(VP  verb phrase)
Morphology
Sentence Structure
Determines stem + ending
e.g. eats  eat + (verb, singular, 3rd)
the dog  NP
eats  verb
the bone  NP
verb  NP VP
(S  sentence)
part of
sentence
structure
Parse Tree
Ambiguity
Several rules applicable:
e.g. VP  verb and VP  verb NP
Semantic Representation
Generate frame-based representation from syntactic structure + lexicon.
(cf. Filmore’s case frames  literature search or ask CRL for set of cases, roles)
Basic idea: Verb-centered representation. Verb (action) is regarded as center of meaning
expression, other parts of sentence are described in relation to the action (as role, or case
fillers).
General Frame for ‘eating’:
Frame for sentence 1:
Agent:
Action:
Patiens:
Manner:
Place:
Time:
Agent: the dog
Action: eat
Patiens: the bone
-
animate
eat
food
{e.g. fast}
{e.g. in the yard}
{e.g. at noon}
-
Example: case, role = Patiens, possible fillers = food (concept), filler in sentence1 = the bone
Sentence types:
Specify grammar for various sentence types (cf. dialogue, discourse grammar).
Distinguish questions, commands, and statements:
 Where is the remote-control?
 Bring the remote-control!
 The remote-control is on the brown table.
Maybe add meta-dialogues, e.g. “Why did you bring the remote control?” – “Because you told
me.”
Interface to Knowledge Base/Planner:
Extract sentence type (as above).
Extract goal/action from frame representation + other information provided, like objects to act
on, or time demands (e.g. immediately).
Procedure:
Determine discourse area, domain words  lexicon
Write possible dialogues  grammar, sentence types,…
Write grammar for syntax analysis, taking different sentence types into account.
Write transformation rules for constructing case frames from grammar (+lexicon).