DETECTLANGUAGE Function Guide

Input text is too short (typically less than 3-5 words), contains only numbers or symbols without alphabetic text, or is in an unsupported language (rare). The language detection algorithm requires sufficient linguistic patterns to make a confident determination. Single words, abbreviations, or numeric content don't provide enough context.

1. **Increase text length:** Ensure input has minimum 3-5 words for basic detection, 20+ words for high accuracy 2. **Check content type:** Verify text contains actual words, not just numbers, dates, or special characters 3. **Validate input:** Use LEN() to check text length before detection 4. **Add fallback:** Use `=IF(ISBLANK(DETECTLANGUAGE(A2)), "Unknown", DETECTLANGUAGE(A2))` to handle empty results gracefully 5. **Combine short texts:** If multiple short text cells need detection, concatenate them: `=DETECTLANGUAGE(A2&" "&B2&" "&C2)`

Implement data validation requiring minimum text length. Add helper columns to count words: `=LEN(A2)-LEN(SUBSTITUTE(A2," ",""))+1`. Only run detection on cells meeting minimum word count (3+ words recommended).

Text is too short for accurate detection, contains specialized terminology appearing in multiple languages, uses words common across languages (e.g., 'taxi', 'hotel', 'ok'), or consists of proper nouns and brand names. Very short texts (1-3 words) may be misidentified because many words exist in multiple languages with similar spelling.

1. **Increase context:** Provide more text for detection (20+ words yields 95%+ accuracy) 2. **Avoid short phrases:** Single words or 2-3 word phrases are inherently ambiguous 3. **Manual override:** For critical applications, create a reference list of known texts and languages 4. **Validate results:** Cross-check detection against known data samples to measure accuracy 5. **User confirmation:** For user-generated content, allow manual language selection with detection as default 6. **Multiple detection passes:** For critical content, detect multiple times and use most common result

Set minimum text length requirements (20 words for business-critical detection). Test accuracy with sample data representing your use case. Maintain a 'known languages' lookup table for important customers or accounts. Document which content types work well vs poorly with detection.

Invalid input type (attempting to detect language of numeric values, dates, or boolean values), formula syntax error in the DETECTLANGUAGE formula, cell reference pointing to non-existent range, or temporary issues with Google's language detection service (rare). Circular reference in formula logic.

1. **Verify input type:** Ensure cell contains text, not numbers or dates. Use `=ISTEXT(A2)` to check 2. **Convert if needed:** Wrap numeric values with TEXT(): `=DETECTLANGUAGE(TEXT(A2,"0"))` 3. **Check syntax:** Verify formula has correct format: `=DETECTLANGUAGE(reference)` with exactly one parameter 4. **Validate references:** Ensure cell references exist and are spelled correctly 5. **Add error wrapper:** Use `=IFERROR(DETECTLANGUAGE(A2), "Error: invalid input")` for graceful handling 6. **Check for circular references:** Ensure formula doesn't reference itself directly or indirectly

Use data validation to ensure only text is entered in detection columns. Add helper columns to verify data types before detection: `=IF(ISTEXT(A2), DETECTLANGUAGE(A2), "Not text")`. Implement IFERROR wrappers in all production formulas.

Detection algorithms may interpret ambiguous short texts differently based on subtle context differences. Minor changes in text (adding/removing a word) can shift language probability scores across the detection threshold. For mixed-language content, small edits can change which language is determined to be dominant. Detection confidence thresholds at boundaries may produce inconsistent results.

1. **Standardize text length:** Maintain consistent minimum text lengths for comparable results 2. **Document edge cases:** Keep a list of known ambiguous terms in your domain and their expected languages 3. **Manual override system:** Create a lookup table for known ambiguous phrases with correct language assignments 4. **Add validation checks:** For business-critical classification, implement secondary validation (e.g., domain knowledge, user profiles) 5. **Use text length as confidence proxy:** `=IF(LEN(A2)>50, DETECTLANGUAGE(A2), "Low confidence")` to flag short texts 6. **Cache results:** For static content, run detection once and copy values (Ctrl+Shift+V) to prevent recalculation variations

Implement minimum text length standards (20+ words for high confidence). Create business rules for edge cases specific to your industry. Test with representative sample data and document accuracy rates. For critical applications, consider human review of detections below confidence threshold.