diff --git a/milli/src/update/index_documents/extract/extract_docid_word_positions.rs b/milli/src/update/index_documents/extract/extract_docid_word_positions.rs
index 67270bc52..ac041a8b0 100644
--- a/milli/src/update/index_documents/extract/extract_docid_word_positions.rs
+++ b/milli/src/update/index_documents/extract/extract_docid_word_positions.rs
@@ -28,8 +28,8 @@ pub fn extract_docid_word_positions<R: io::Read + io::Seek>(
     indexer: GrenadParameters,
     searchable_fields: &Option<HashSet<FieldId>>,
     stop_words: Option<&fst::Set<&[u8]>>,
-    allowed_separators: Option<&Vec<&str>>,
-    dictionary: Option<&Vec<&str>>,
+    allowed_separators: Option<&[&str]>,
+    dictionary: Option<&[&str]>,
     max_positions_per_attributes: Option<u32>,
 ) -> Result<(RoaringBitmap, grenad::Reader<File>, ScriptLanguageDocidsMap)> {
     puffin::profile_function!();
@@ -55,10 +55,10 @@ pub fn extract_docid_word_positions<R: io::Read + io::Seek>(
         tokenizer_builder.stop_words(stop_words);
     }
     if let Some(dictionary) = dictionary {
-        tokenizer_builder.words_dict(dictionary.as_slice());
+        tokenizer_builder.words_dict(dictionary);
     }
     if let Some(separators) = allowed_separators {
-        tokenizer_builder.separators(separators.as_slice());
+        tokenizer_builder.separators(separators);
     }
     let tokenizer = tokenizer_builder.build();
 
diff --git a/milli/src/update/index_documents/extract/mod.rs b/milli/src/update/index_documents/extract/mod.rs
index cec0d5814..4e174631c 100644
--- a/milli/src/update/index_documents/extract/mod.rs
+++ b/milli/src/update/index_documents/extract/mod.rs
@@ -49,8 +49,8 @@ pub(crate) fn data_from_obkv_documents(
     geo_fields_ids: Option<(FieldId, FieldId)>,
     vectors_field_id: Option<FieldId>,
     stop_words: Option<fst::Set<&[u8]>>,
-    allowed_separators: Option<Vec<&str>>,
-    dictionary: Option<Vec<&str>>,
+    allowed_separators: Option<&[&str]>,
+    dictionary: Option<&[&str]>,
     max_positions_per_attributes: Option<u32>,
     exact_attributes: HashSet<FieldId>,
 ) -> Result<()> {
@@ -293,8 +293,8 @@ fn send_and_extract_flattened_documents_data(
     geo_fields_ids: Option<(FieldId, FieldId)>,
     vectors_field_id: Option<FieldId>,
     stop_words: &Option<fst::Set<&[u8]>>,
-    allowed_separators: &Option<Vec<&str>>,
-    dictionary: &Option<Vec<&str>>,
+    allowed_separators: &Option<&[&str]>,
+    dictionary: &Option<&[&str]>,
     max_positions_per_attributes: Option<u32>,
 ) -> Result<(
     grenad::Reader<CursorClonableMmap>,
@@ -350,8 +350,8 @@ fn send_and_extract_flattened_documents_data(
                         indexer,
                         searchable_fields,
                         stop_words.as_ref(),
-                        allowed_separators.as_ref(),
-                        dictionary.as_ref(),
+                        *allowed_separators,
+                        *dictionary,
                         max_positions_per_attributes,
                     )?;
 
diff --git a/milli/src/update/index_documents/mod.rs b/milli/src/update/index_documents/mod.rs
index 5426e26db..0dae611c9 100644
--- a/milli/src/update/index_documents/mod.rs
+++ b/milli/src/update/index_documents/mod.rs
@@ -359,8 +359,8 @@ where
                     geo_fields_ids,
                     vectors_field_id,
                     stop_words,
-                    separators,
-                    dictionary,
+                    separators.as_ref().map(Vec::as_slice),
+                    dictionary.as_ref().map(Vec::as_slice),
                     max_positions_per_attributes,
                     exact_attributes,
                 )