Two experiments were conducted to determine whether a parser's on-line proc
esses are affected by manipulation of case markings in Korean sentence proc
essing, and to evaluate the usefulness of a Ranked Flagged Serial Parser (R
FSP) model in predicting Korean ambiguity resolution processes, By using a
self-paced word-by-word reading task, in Experiment 1, relative and coordin
ate sentences of the form NP-ka (nominative), NP-lul (accusative), and Verb
were compared to those sentences of the form NP-nun (topic marker), NP-lul
, and Verb. In Experiment 2, relative sentences that have NP-ka, NP-ka, and
Verb sequence were compared to those sentences of NP-nun, NP-ka, and Verb
sequence. In addition, reversed relative clause sentences were compared aft
er changing case markings of the last NP. The topic marker -nun changed ove
rall patterns of word-by-word reading times of the sentences in both experi
ments. The results clearly-showed that local grammatical cues, such as case
markings, are used in generating syntactic hypotheses. We also found that
the RFSP model successfully predicted local processing loads and reparsing
difficulties in Korean sentence comprehension. Suggestions for further stud
ies were made.