A Treebank-based Investigation of IPP-triggering Verbs in Dutch

Det Adj N
(a) Danish
Det Adj N
(b) Swedish/Norwegian
Figure 1: Noun phrase annotation
bank that fall below a certain perplexity threshold. All experiments are performed
with dependency representations, using MSTparser (McDonald et al. [5]). The
work shows that the filtering approach yields considerable improvements over the
simple technique proposed by Zeman and Resnik [12] when applied to unrelated
languages.
The above approaches to parser adaptation train delexicalized parsers on the
(unfiltered or filtered) source language data, however, there are clearly many lexical
patterns that are similar cross-lingually if one finds the right level of abstraction.
Täckström et al. [10] investigate the use of cross-lingual word clusters derived
using parallel texts in order to add some level of lexical information that abstracts
over individual words.
2 Treebanks
In all our experiments, the target language is Norwegian, and either Swedish or
Danish is used as the source. For these experiments, we used three treebanks: the
Danish Dependency Treebank (DDT) (Kromann [4]) and the Swedish Talbanken05
(Nivre et al. [6]), both from the 2006 CoNLL shared task on multilingual dependency
parsing, and an in-development Norwegian treebank being prepared by the
Norwegian national library (NDT) 2 . Of the three, Talbanken is by far the largest,
with some 11000 sentences in the training set. The DDT is smaller with about 5200
sentences of training data, and the NDT even smaller with 4400 sentences all told.
The Scandinavian languages, Danish, Norwegian and Swedish, are extremely
closely related to one another. The split of Norse into the modern-day Scandinavian
languages is very recent 3 , which means that the languages are mutually
intelligible to a large extent, and share a large number of syntactic and morphological
features, and have a large common vocabulary. Perhaps the largest difference
is orthographical conventions.
Our treebanks are more diverse than the languages they are based on. As Zeman
and Resnik [12] point out, Talbanken and DDT are different in many respects;
most of these differences are due to DDT preferring functional heads while Tal-
2 A beta release is available at http://www.nb.no/spraakbanken/
tilgjengelege-ressursar/tekstressursar
3 Within the last 1000 to 500 years. For comparison, the split between German and Dutch is some
500 years before this.
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