...
Navigate to the Engine → Workbench → Keyword Search→ Auto-complete
Click the Update Top Product
If existing remove any value for the Name/Value field. In this case - Title
Click the Save button
Rebuild the index
In the Hawksearch Box or Hawksearch results (SPA Mode) widget designer Data field, add the {"_suggestionItem":{"titleField":"field-name"}} to the Data object. For the value of the titleField, you must enter the field that you want to perform the autocomplete search without the language suffix, e.g. title
Click Save
Publish the page
Facet visualization when using the multilingual functionality
...