You can use ML Kit to identify the language of a string of text. You can get the string's most likely language or get confidence scores for all of the string's possible languages.
ML Kit recognizes text in 103 different languages in their native scripts. In addition, romanized text can be recognized for Arabic, Bulgarian, Chinese, Greek, Hindi, Japanese, and Russian.
Before you begin
- If you haven't already, add Firebase to your Android project .
- Add the dependencies for the ML Kit Android libraries to your module
(app-level) Gradle file (usually
app/build.gradle):apply plugin : ' com . android . application ' apply plugin : ' com . google . gms . google - services ' dependencies { // ... implementation ' com . google . firebase : firebase - ml - natural - language : 22.0.0 ' implementation ' com . google . firebase : firebase - ml - natural - language - language - id - model : 20.0.7 ' }
Identify the language of a string
To identify the language of a string, get an instance of FirebaseLanguageIdentification
, and then pass the string to the identifyLanguage()
method.
For example:
FirebaseLanguageIdentification
languageIdentifier
=
FirebaseNaturalLanguage
.
getInstance
().
getLanguageIdentification
();
languageIdentifier
.
identifyLanguage
(
text
)
.
addOnSuccessListener
(
new
OnSuccessListener<String>
()
{
@Override
public
void
onSuccess
(
@Nullable
String
languageCode
)
{
if
(
languageCode
!=
"und"
)
{
Log
.
i
(
TAG
,
"Language: "
+
languageCode
);
}
else
{
Log
.
i
(
TAG
,
"Can't identify language."
);
}
}
})
.
addOnFailureListener
(
new
OnFailureListener
()
{
@Override
public
void
onFailure
(
@NonNull
Exception
e
)
{
// Model couldn’t be loaded or other internal error.
// ...
}
});
If the call succeeds, a BCP-47 language code
is
passed to the success listener, indicating the language of the text. See the complete list of supported languages
. If no
language could be confidently detected, the code und
(undetermined) is passed.
By default, ML Kit returns a value other than und
only when it identifies
the language with a confidence value of at least 0.5. You can change this
threshold by passing a FirebaseLanguageIdentificationOptions
object to getLanguageIdentification()
:
FirebaseLanguageIdentification
languageIdentifier
=
FirebaseNaturalLanguage
.
getInstance
()
.
getLanguageIdentification
(
new
FirebaseLanguageIdentificationOptions
.
Builder
()
.
setIdentifyLanguageConfidenceThreshold
(
0.34f
)
.
build
());
Get the possible languages of a string
To get the confidence values of a string's most likely languages, get an
instance of FirebaseLanguageIdentification
, and then pass the string to the identifyAllLanguages()
method.
For example:
FirebaseLanguageIdentification
languageIdentifier
=
FirebaseNaturalLanguage
.
getInstance
().
getLanguageIdentification
();
languageIdentifier
.
identifyAllLanguages
(
text
)
.
addOnSuccessListener
(
new
OnSuccessListener<String>
()
{
@Override
public
void
onSuccess
(
List<IdentifiedLanguage>
identifiedLanguages
)
{
for
(
IdentifiedLanguage
identifiedLanguage
:
identifiedLanguages
)
{
String
language
=
identifiedLanguage
.
getLanguageCode
();
float
confidence
=
identifiedLanguage
.
getConfidence
();
Log
.
i
(
TAG
,
language
+
" ("
+
confidence
+
")"
);
}
}
})
.
addOnFailureListener
(
new
OnFailureListener
()
{
@Override
public
void
onFailure
(
@NonNull
Exception
e
)
{
// Model couldn’t be loaded or other internal error.
// ...
}
});
If the call succeeds, a list of IdentifiedLanguage
objects is passed to the
success listener. From each object, you can get the language's BCP-47 code and
the confidence that the string is in that language. See the complete list of supported languages
. Note that
these values indicate the confidence that the entire string is in the given
language; ML Kit doesn't identify multiple languages in a single string.
By default, ML Kit returns only languages with confidence values of at least
0.01. You can change this threshold by passing a FirebaseLanguageIdentificationOptions
object to getLanguageIdentification()
:
FirebaseLanguageIdentification
languageIdentifier
=
FirebaseNaturalLanguage
.
getInstance
()
.
getLanguageIdentification
(
new
FirebaseLanguageIdentificationOptions
.
Builder
()
.
setIdentifyAllLanguagesConfidenceThreshold
(
0.5f
)
.
build
());
If no language meets this threshold, the list will have one item, with the value und
.
