A lemmatizer is a program that finds a word's lemma or lemmas.
The lemma is the head word of a morphological family, the root; it is the word that we would be difined in a dictionary.
Most words in Spanish are inflected words. Given an inflected word, this program obtains its lemma and the meaning of its inflection.
For example, given the word "perritas" the lemmatizer will determine it comes from the lemma "perro" with the attributes femenine, plural and diminutive.
Similarly, if we enter the word "leerá", the program will reveal it's the third person, singular, of the future indicative of the verb "leer".

The lemmatizer can find all possible lemmas of a given word, thus, the lemmatizer will inform us that for the word
"suma":

• It is the root of the noun "suma".
• It is the third person singular of the present indicative of the verb "sumar".
• It is the third person singular of the imperative of the verb "sumir".
• It is the femenine singular of the adjective "sumo".