A library for eXtensible Interlinear Glossed Text (IGT)

• Installation and Requirements
• Features
• Acknowledgments

Xigt is created with extensibility in mind, offering a core framework and XML schema (in RelaxNG) ready to be extended without much trouble. Here is a small example of an IGT encoded in Xigt's XML format:

<igt id="i1" lg="spa">
  <tier type="words" id="w">
    <item id="w1">cocinas</item>
  </tier>
  <tier type="morphemes" id="m" segmentation="w">
    <item id="m1" segmentation="w1[0:5]"/>
    <item id="m2" segmentation="w1[5:7]"/>
  </tier>
  <tier type="glosses" id="g" alignment="m">
    <item id="g1" alignment="m1">cook</item>
    <item id="g2" alignment="m2">2</item>
    <item id="g3" alignment="m2">SG</item>
    <item id="g4" alignment="m2">PRS</item>
    <item id="g5" alignment="m2">IND</item>
  </tier>
</igt>

Xigt requires the following:

• Python3

For using Xigt's XML format, we recommend you also install:

• A RelaxNG validator for compact schema, like Jing
• The lxml XML library for Python

After downloading Xigt, install it with the setup.py command:

$ ./setup.py install

Note: To remove (uninstall) Xigt, remove its package directory. On a Linux system, this may somewhere like /usr/lib/python3.X/site-packages/xigt/. There may also be an Egg info file, such as /usr/lib/python3.X/site-packages/Xigt-(version)-py3.X.egg-info.

Xigt has several features that help enable complex alignments, and these features can be ignored for simpler IGT.

Given:

<item id="a1">one</item>
<item id="a2">two</item>

The following alignment expressions will align to the following selections:

a1                  -> "one"
a1,a2               -> "one two"
a1+a2               -> "onetwo"
a1[0:1]             -> "o"
a1[0:1,2:3]         -> "oe"
a1[1:3]+a2[1:2+0:1] -> "newt"

When more than one item align to the same selection, they are in a floating alignment. That is, they are ordered (as in the XML), but have no definite subpartitioning among them. For instance, given the following item:

<item id="s1">A dog barks.</item>

...and the following aligned items all aligned to the same item above:

<item id="w1" alignment="s1">A</item>
<item id="w2" alignment="s1">dog</item>
<item id="w3" alignment="s1">barks</item>

Xigt will maintain the order ["A", "dog", "barks"] (i.e. not ["dog", "A", "barks"] and so on), but does not specify the selections (i.e. character spans) from the aligned item. In other words, it is understood that w1, w2, and w3 are contained by s1 and in that order, but there is no explicit character alignments. This is useful when one does not want to delimit items exactly, or when one cannot delimit the sub-items (e.g. glosses for portmanteau morphemes).

Items can provide content, but if they don't, they inherit it from other items using the content or segmentation reference attributes. The content attribute may be used when providing annotation and the annotation content comes from another source (e.g. a standoff annotation). The segmentation attribute is useful when merely breaking up sentences into words, words into morphemes, etc., as it accomplishes two things: pulling content from and aligning to a span. The alignment during segmentation is necessary to later find where the content came from.

For example, one can delimit the morphemes of the word in item w3 above as follows:

<item id="w3" alignment="s1">barks</item>
...
<item id="m1" segmentation="w3[0:4]"/>
<item id="m2" segmentation="w3[4:5]"/>

Items m1 and m2 do not provide their own content, so their content is inherited from the specified spans of w3. That is, m1's content is implicitly "bark", and m2's is implicitly "s". Later items refer to the relative character positions of the inherited content. For example, referencing "m2[0:1]" is the character "s" (aside: since it's the entire content of m2, it's the same as referencing "m2").

Also note that an item can specify both a segmentation attribute and provide content. This is useful when one wants the alignment of the segmentation to show where the content came from, but also want to provide different content. For example, one may use this to clean up OCR results or show the underlying form before phonological processes have occurred.

When an item x provides content, later items referring to x can only select alignments to x's content, and not that of any items x refers to. For example, in the following, the content of y is "t", and not "o".

<item id="w">one</item>
...
<item id="x" segmentation="w">two</item>
...
<item id="y" segmentation="x[0:1]"/>

This material is based upon work supported by the National Science Foundation under Grant No. 1160274.Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Xigt was developed under the AGGREGATION project (http://depts.washington.edu/uwcl/aggregation/)