Alter utterance data before or during prediction


LUIS will be retired on October 1st 2025 and starting April 1st 2023 you will not be able to create new LUIS resources. We recommend migrating your LUIS applications to conversational language understanding to benefit from continued product support and multilingual capabilities.

LUIS provides ways to manipulate the utterance before or during the prediction. These include fixing spelling, and fixing timezone issues for prebuilt datetimeV2.

Correct spelling errors in utterance

V3 runtime

Preprocess text for spelling corrections before you send the utterance to LUIS. Use example utterances with the correct spelling to ensure you get the correct predictions.

Use Bing Spell Check to correct text before sending it to LUIS.

Prior to V3 runtime

LUIS uses Bing Spell Check API V7 to correct spelling errors in the utterance. LUIS needs the key associated with that service. Create the key, then add the key as a querystring parameter at the endpoint.

The endpoint requires two params for spelling corrections to work:

Param Value
spellCheck boolean
bing-spell-check-subscription-key Bing Spell Check API V7 endpoint key

When Bing Spell Check API V7 detects an error, the original utterance, and the corrected utterance are returned along with predictions from the endpoint.

  "query": "Book a flite to London?",
  "alteredQuery": "Book a flight to London?",
  "topScoringIntent": {
    "intent": "BookFlight",
    "score": 0.780123
  "entities": []

List of allowed words

The Bing spell check API used in LUIS does not support a list of words to ignore during the spell check alterations. If you need to allow a list of words or acronyms, process the utterance in the client application before sending the utterance to LUIS for intent prediction.

Change time zone of prebuilt datetimeV2 entity

When a LUIS app uses the prebuilt datetimeV2 entity, a datetime value can be returned in the prediction response. The timezone of the request is used to determine the correct datetime to return. If the request is coming from a bot or another centralized application before getting to LUIS, correct the timezone LUIS uses.

V3 prediction API to alter timezone

In V3, the datetimeReference determines the timezone offset. Learn more about V3 predictions.

V2 prediction API to alter timezone

The timezone is corrected by adding the user's timezone to the endpoint using the timezoneOffset parameter based on the API version. The value of the parameter should be the positive or negative number, in minutes, to alter the time.

V2 prediction daylight savings example

If you need the returned prebuilt datetimeV2 to adjust for daylight savings time, you should use the querystring parameter with a +/- value in minutes for the endpoint query.

Add 60 minutes:

https://{region}{appId}?q=Turn the lights on?timezoneOffset=60&verbose={boolean}&spellCheck={boolean}&staging={boolean}&bing-spell-check-subscription-key={string}&log={boolean}

Remove 60 minutes:

https://{region}{appId}?q=Turn the lights on?timezoneOffset=-60&verbose={boolean}&spellCheck={boolean}&staging={boolean}&bing-spell-check-subscription-key={string}&log={boolean}

V2 prediction C# code determines correct value of parameter

The following C# code uses the TimeZoneInfo class's FindSystemTimeZoneById method to determine the correct offset value based on system time:

// Get CST zone id
TimeZoneInfo targetZone = TimeZoneInfo.FindSystemTimeZoneById("Central Standard Time");

// Get local machine's value of Now
DateTime utcDatetime = DateTime.UtcNow;

// Get Central Standard Time value of Now
DateTime cstDatetime = TimeZoneInfo.ConvertTimeFromUtc(utcDatetime, targetZone);

// Find timezoneOffset/datetimeReference
int offset = (int)((cstDatetime - utcDatetime).TotalMinutes);

Next steps

Correct spelling mistakes with this tutorial