Lecture 4. Parsing

Ekaterina Chernyak, Dmitry Ilvovsky

Two approaches to grammar modeling

Constituency grammar [Martin, Jurafsky, 2000]

Phrase structure organizes words into nested constituents

Dependency grammar [Martin, Jurafsky, 2000]

Dependency structure shows which words depend on (modify or are arguments of) which other words.

Constituency VS dependency grammar (1)

Constituency VS dependency grammar (1)

Constituency VS dependency grammar (2)

Exercise 4.1

Construct constituency and dependency trees for the sentences:

• "Susan wants to marry Lary."
• "They saw a man with the telescope."
• "Why do we say that the earth moves around the sun?"

Demos

• Berkley Tomcat constituency parser [1]
• Stanford CoreNLP dependency parser [2]
• ARK dependency parser (Carnegie Melon) [3]