Morphological Recognition

Inflectional morphology is combining a word stem with a grammatical morpheme producing a word (usuallY) of the same class. Inflection addresses such things as number agreement, person agreement and tense.

To create a recognizer (or generator or more generally, to morphologically parse) for the morphemes of a word, one needs:

Finite State Recognizers

• Number recognition.

                           --------
                          | ------ |   -s    ------ 
            ----   reg-n  ||      || plural | -----|  
           |    |--------→||      ||-------→||    ||   
      ----→| q0 |         ||  q1  ||        || q2 ||   
            ----          ||      ||        ||    ||  
            | |           | ------ |        | ---- |
            | |            ---------         ------
            | |                               ↑  ↑
            | |     irreg-pl-noun             |  |
            |  -------------------------------   |            
             ------------------------------------                        
                    irreg-sg-noun                                      
                                                          

• Inflection — tense

                            irreg-past-verb-form
             ------------------------------------------------
             |                                               |
             |                    --------                   ↓
             |                   | ------ |   preterite    ------ 
            ----   reg-verb-stem ||      ||    (-ed)      | -----|  
           |    |---------------→||      ||--------------→||    ||   
      ----→| q0 |                ||  q1  ||               || q3 ||   
            ----                 ||      ||--------------→||    ||  
            | |                  | ------ | past part     | ---- |
            | |                   ---------    (-ed)       ------
            | |                                             ↑   ↑
            | |                   --------                  |   |
            | |  reg-verb-stem   | ------ |                 |   | 
            |  -----------------→||      || prog (-ing)     |   | 
            |                    ||      ||-----------------    |   
             -------------------→||  q2  ||---------------------
              irreg-verb-stem    ||      ||     3-sing (-s)   
                                 | ------ |                     
                                  ---------                      
                                                                  

• Productive morpheme recognition — comparison

                       --------              ------    -er  -est   ------ 
       ----   un-     |        |  adj-root  | -----|      -ly     | -----|  
      |    |---------→|        |-----------→||    ||-------------→||    ||   
 -----| q0 |          |   q1   |            || q2 ||              || q3 ||   
       ----           |        |            ||    ||-------------→||    ||  
                      |        |            | ---- |              | ---- |
                       --------              ------                ------

• Derivational morpheme recognition


                       --------              ------                ------        ------ 
       ----  noun     | -----  |  -ize/V    | -----|  -ation/N    | -----|      | -----|
      |    |---------→||     | |-----------→||    ||-------------→||    ||      ||    ||
 -----| q0 |---------→||  q1 | |            || q2 ||              || q3 ||      || q4 ||
       ----  adj-al   ||     | |            ||    ||-----         ||    || .---→||    ||
       |||||          | -----  |  .---------| ---- |     |        | ---- | |    | ---- |
       |||||           --------   | -able/A  ------      |         ------  |     ------
       |||||                      |                      ------------------             
       |||||                      ↓                           -er/N                     
       |||||                  ------                ------ 
       |||||  adj-al         | ---- |  -ity/N      | -----|  
       |||| ----------------→||    ||-------------→||    ||   
       ||||                  || q5 ||              || q6 ||   
       ||||                  ||    ||-------------→||    ||  
       ||||                  | ---- |  -ness/N     | ---- |
       ||||                   ------                ------
       ||||                     |                      ↑                  
       ||||                     |                      |             ------ 
       ||||                     |                    -ness/N        | -----|  
       ||||                      ----------------------------------→||    ||   
       ||||                                -ly/Adv     |            || q9 ||   
       ||||                                            |  .--------→||    ||  
       ||||         adj-ous                            |  |         | ---- |
       ||| --------------------------                  |  |          ------
       |||                           |                 |  |               
       |||               ------      |         ------  |  | -ly/Adv
       |||              | -----|     |        | -----| |  |
       |||              ||    ||      -------→||    ||-   |
       || -------------→|| q7 ||              || q8 ||    |
       ||     verb      ||    ||-------------→||    ||----
       ||               | ---- |     -ive/A   | ---- |
       ||                ------                ------
       ||                                       ↑   ↑             
       ||                                       |   |                       
       ||         ------                        |   |   
       ||        | -----|                       |   |   
       ||        ||    ||                       |   |   
       | -------→|| q10||------------------------   | 
       |  verb   ||    ||   -ative/A                | 
       |         | ---- |                           | -ful/A        
       |          ------                            |               
       |                                            |                     
       |                                            |                     
       |                                ------      |
       |                               | -----|     |
       |          noun                 ||    ||-----
        ------------------------------→|| q11||   
                                       ||    ||  
                                       | ---- |
                                        ------