Translate a part of speech

main.rb

@@ -22,7 +22,7 @@ before do
 end
 
 get '/words/:id' do
-  Context.call db_pool: $DB_POOL, user_lang_id: nil do |context|
+  Context.call db_pool: $DB_POOL, user_lang_id: 2 do |context|
     word_id = Integer params[:id]
 
     json({
@@ -76,15 +76,23 @@ public
     column = @db_conn.exec_params(
       (
         <<~SQL
-          SELECT parts.english_name
+          SELECT part_names.value
           FROM words
           INNER JOIN parts
           ON words.part_id = parts.id
-          WHERE words.id = $1
+          INNER JOIN part_names
+          ON part_names.part_id = parts.id
+          WHERE
+            words.id = $1
+            AND (
+              part_names.name_lang_id = $2
+              OR
+              $2 IS NULL
+            )
           LIMIT 1
         SQL
       ),
-      [word_id],
+      [word_id, user_lang_id],
     ).values.first&.first
 
     str = String(column).strip.freeze