Afrikaans Lemmatizer

Description

This is a dictionary-based lemmatizer that assigns all forms and inflections of a word to a single root. This enables the pipeline to treat the past and present tense of a verb, for example, as the same word instead of two completely different words.

Live Demo Open in Colab Download

How to use

document_assembler = DocumentAssembler() \
    .setInputCol("text") \
    .setOutputCol("document")

tokenizer = Tokenizer()\
    .setInputCols(["document"]) \
    .setOutputCol("token")

lemmatizer = LemmatizerModel.pretrained("lemma", "af") \
        .setInputCols(["token"]) \
        .setOutputCol("lemma")

nlp_pipeline = Pipeline(stages=[document_assembler, tokenizer, lemmatizer])
model = pipeline.fit(spark.createDataFrame([['']]).toDF("text"))

results = model.transform(["Ons het besliste teen-resessiebesteding deur die regering geïmplementeer , veral op infrastruktuur ."])


val document_assembler = DocumentAssembler()
    .setInputCol("text")
    .setOutputCol("document")

val tokenizer = Tokenizer()
    .setInputCols(["document"])
    .setOutputCol("token")

val lemmatizer = LemmatizerModel.pretrained("lemma", "af")
        .setInputCols(["token"])
        .setOutputCol("lemma")

val pipeline = new Pipeline().setStages(Array(document_assembler, tokenizer, lemmatizer))
val data = Seq("Ons het besliste teen-resessiebesteding deur die regering geïmplementeer , veral op infrastruktuur .").toDF("text")
val result = pipeline.fit(data).transform(data)


import nlu

text = ["Ons het besliste teen-resessiebesteding deur die regering geïmplementeer , veral op infrastruktuur ."]
lemma_df = nlu.load('af.lemma').predict(text, output_level = "document")
lemma_df.lemma.values[0]

Results

+--------------------+
|               lemma|
+--------------------+
|                 ons|
|                 het|
|              beslis|
|teen-resessiebest...|
|                deur|
|                 die|
|            regering|
|        implementeer|
|                   ,|
|               veral|
|                  op|
|      infrastruktuur|
|                   .|
+--------------------+

Model Information

Model Name: lemma
Compatibility: Spark NLP 2.7.5+
License: Open Source
Edition: Official
Input Labels: [token]
Output Labels: [lemma]
Language: af

Data Source

The model was trained on the Universal Dependencies version 2.7.

Benchmarking

Precision=0.81, Recall=0.78, F1-score=0.79