# LanguageDetection **`class LanguageDetection(config)`** Bases: [`BatchedStep`](../technical/libnlp/steps/standard.md#squirro.lib.nlp.steps.batched_step.BatchedStep) Perform language detection on document. Parameters - `step` ([`str`](https://docs.python.org/3.11/library/stdtypes.html#str)`, ``"app"`) – app - `type` ([`str`](https://docs.python.org/3.11/library/stdtypes.html#str)`, ``"query_processing"`) – query_processing - `name` ([`str`](https://docs.python.org/3.11/library/stdtypes.html#str)`, ``"lang_detection"`) – lang_detection - `input_field` ([`str`](https://docs.python.org/3.11/library/stdtypes.html#str)`,``"user_terms_str"`) – query - `output_field` ([`str`](https://docs.python.org/3.11/library/stdtypes.html#str)`,``"language"`) – detected language as ISO code - `fallback_language` ([`str`](https://docs.python.org/3.11/library/stdtypes.html#str)`, ``"en"`) – Default language to use - `path` ([`str`](https://docs.python.org/3.11/library/stdtypes.html#str)`, ``"."`) – path Attributes SummaryMethods SummaryAttributes Documentation **`MODEL_CACHE_KEY = 'fasttext_language_detector'`** Methods Documentation **`process_doc(doc)`** Process a document Parameters `doc` ([`Document`](../technical/libnlp/base.md#squirro.lib.nlp.document.Document)) – Document Returns Processed document Return type [Document](../technical/libnlp/base.md#squirro.lib.nlp.document.Document)