■What is NINJAL-LWP for TWC?

NINJAL-LWP for TWC (NLT) is a tool for searching the Tsukuba Web Corpus (TWC), a corpus of approximately 1.1 billion words collected from Japanese-language websites. The search function is based on the use of NINJAL-LWP (NINJAL-LagoWordProfiler), a corpus search system developed jointly by the National Institute for Japanese Language and Linguistics (NINJAL) and Lago Institute of Language. Among tools that utilize the same system is NINJAL-LWP for the BCCWJ (NLB), a tool for searching the 100-million-word Balanced Corpus of Contemporary Written Japanese (BCCWJ), which was developed by NINJAL.

This tool uses a method known as lexical profiling to comprehensively indicate the co-occurrence relations and grammatical behavior of nouns, verbs, and other content words.

■How to Use

With a concordancer, the results obtained by inputting a search string are returned as concordance lines. With NLT, you first select the word you wish to look up (referred to with NLT as a “headword”) rather than input a search string. There are five types of content words that can be looked up as node words: nouns, verbs, adjectives, adnominal adjectives and adverbs.

To illustrate, let us look up the verb “run”. First, enter “走る”, “はしる” (or with katakana characters), or “hashiru” in the input field on the screen and click the “Refine” button. Three node words that can be read as “はしる” appear in the list below; click on the “走る” that appears at the top of this list.

Click to open a node word window for “走る”. At this stage, you can try to figure out what nouns might appear before “が走る”. If you select “By group” in the left-hand panel of grammatical patterns, the “noun + postpositional particle <” group will appear at the top. Click on the “…が走る” pattern at the top.

Collocations of “noun + が走る” will then appear in order of frequency in the collocation panel in the center of the screen. In the left-hand example panel, the most frequent example, “車が走る” (“a car is driven”), is shown.

Next, let us bring up characteristic collocations. With NLT, you can sort a list not just by frequency but also by MI score. The MI score is a statistical indicator that tends to be higher for more characteristic collocations. However, low-frequency collocations need to be excluded since they would otherwise be over-represented. Click on “MI” in the header of the collocation panel and then right-click on the top of the panel and select “Frequency of 20 or more”.

You will then see such characteristic expressions of “noun + が走る” as “虫ずが走る” (“to be disgusted”) and “戦慄が走る” (“a shudder running through”) appear at the top.

Click on each collocation to bring up corresponding examples in the right-hand panel. In this case, click on the seventh collocation: “閃光が走る” (“light flashes”). You can then individually check out actual examples as used in the corpus.

Examples are shown in sentences. If you wish to check out the context for an example sentence, click on the source for the example sentence in question to open up a dialog window that displays the sentences that appear before and after the example sentence.

In this way, NLT allows you to first select a node word in the search window and then, in the node word window, go back and forth between grammatical patterns, collocations, and examples to obtain a complete picture of the way the node word behaves. Since this tool can be easily operated just by engaging in clicking actions, you can look up a wide range of expressions tied to a node word at will without losing your train of thought.

See the user guide (PDF file, approx. 2.8 MB, Japanese) for more detailed instructions.

■Building the Tsukuba Web Corpus

TWC ver. 1.40 utilizes data consisting of 1,138 million words collected from Japanese-language websites.

In collecting text from the Internet, we went with a typical method by which we used a search engine API to collect web page URLs and then collected data from these URLs. The following are the specific steps we used to build our corpus.

■Annotations

In order to extract information on collocation and grammatical behavior with NLT, we applied annotations to the BCCWJ data and analyzed this data. The analyzers and dictionaries used for these annotations are set forth below.

■Terms of Use

■Headword Frequency List

This is a list of headword frequencies as compiled in an Excel file format (.xlsx). The use of this list is limited to research and educational purposes. For more information, read the “Terms of Use” section in the file.

NLT 1.40 Headword Frequency List

■History of Updates

■Inquiries

Inquiries concerning NLT should be submitted to the following:

jp-kyoten(insert an at mark here)un.tsukuba.ac.jp