2.3.4 From the Intermediate Form to the Morphological Structure

Map the intermediate form that we produced in the previous section to the underlying form.

Now, we want to take the intermediate form that we produced in the previous section and map it to the underlying form. The input that this transducer has to accept is of one of the following forms:

1. regular noun stem, e.g. cat

2. regular noun stem + s, e.g. cat + s

3. singular irregular noun stem, e.g. mouse

4. plural irregular noun stem, e.g. mice

In the first case, the transducer has to map all symbols of the stem to themselves and then output N and SG. In the second case, it maps all symbols of the stem to themselves, but then outputs N and replaces PL with s. In the third case, it does the same as in the first case. Finally, in the fourth case, the transducer should map the irregular plural noun stem to the corresponding singular stem (e.g. mice to mouse) and then it should add N and PL. So, the general structure of this transducer looks like this:

What still needs to be specified is how exactly the parts between state 1 and states 2,3, and 4 respectively look like. Here, we need to recognize noun stems and decide whether they are regular or not. We do this be encoding a lexicon in the following way. The transducer part that recognizes cat, for instance, looks like this:

And the transducer part mapping mice to mouse can be specified as follows:

Plugging these (partial) transducers into the transducer given above we get a transducer that checks that input has the right form and adds category and numerus information.