Error while adding Estonian language to solr 8.1

Question

I am trying to add Estonian language in solr but it giving the error analytics: org.apache.solr.common.SolrException:org.apache.solr.common.SolrException: Could not load conf for core analytics: Error loading class 'org.tartarus.snowball.ext.EstonianStemmer'

I added this in /conf/schema.xml

<fieldType name="text_et" class="solr.TextField" positionIncrementGap="100">
 <analyzer>
     <tokenizer class="solr.StandardTokenizerFactory"/>
     <filter class="solr.LowerCaseFilterFactory"/>
     <filter class="solr.StopFilterFactory" ignoreCase="true" words="lang/stopwords_et.txt" />
     <filter class="solr.SnowballPorterFilterFactory" language="Estonian"/>
 </analyzer>
</fieldType>

and stoptwords too.