diff --git a/core/java/com/android/internal/inputmethod/InputMethodUtils.java b/core/java/com/android/internal/inputmethod/InputMethodUtils.java
index ac17cbe..742173b 100644
--- a/core/java/com/android/internal/inputmethod/InputMethodUtils.java
+++ b/core/java/com/android/internal/inputmethod/InputMethodUtils.java
@@ -1302,4 +1302,131 @@
             return enabledInputMethodAndSubtypes;
         }
     }
+
+    // For spell checker service manager.
+    // TODO: Should we have TextServicesUtils.java?
+    private static final Locale LOCALE_EN_US = new Locale("en", "US");
+    private static final Locale LOCALE_EN_GB = new Locale("en", "GB");
+
+    /**
+     * Returns a list of {@link Locale} in the order of appropriateness for the default spell
+     * checker service.
+     *
+     * <p>If the system language is English, and the region is also explicitly specified in the
+     * system locale, the following fallback order will be applied.</p>
+     * <ul>
+     * <li>(system-locale-language, system-locale-region, system-locale-variant) (if exists)</li>
+     * <li>(system-locale-language, system-locale-region)</li>
+     * <li>("en", "US")</li>
+     * <li>("en", "GB")</li>
+     * <li>("en")</li>
+     * </ul>
+     *
+     * <p>If the system language is English, but no region is specified in the system locale,
+     * the following fallback order will be applied.</p>
+     * <ul>
+     * <li>("en")</li>
+     * <li>("en", "US")</li>
+     * <li>("en", "GB")</li>
+     * </ul>
+     *
+     * <p>If the system language is not English, the following fallback order will be applied.</p>
+     * <ul>
+     * <li>(system-locale-language, system-locale-region, system-locale-variant) (if exists)</li>
+     * <li>(system-locale-language, system-locale-region) (if exists)</li>
+     * <li>(system-locale-language) (if exists)</li>
+     * <li>("en", "US")</li>
+     * <li>("en", "GB")</li>
+     * <li>("en")</li>
+     * </ul>
+     *
+     * @param systemLocale the current system locale to be taken into consideration.
+     * @return a list of {@link Locale}. The first one is considered to be most appropriate.
+     */
+    @VisibleForTesting
+    public static ArrayList<Locale> getSuitableLocalesForSpellChecker(
+            @Nullable final Locale systemLocale) {
+        final Locale systemLocaleLanguageCountryVariant;
+        final Locale systemLocaleLanguageCountry;
+        final Locale systemLocaleLanguage;
+        if (systemLocale != null) {
+            final String language = systemLocale.getLanguage();
+            final boolean hasLanguage = !TextUtils.isEmpty(language);
+            final String country = systemLocale.getCountry();
+            final boolean hasCountry = !TextUtils.isEmpty(country);
+            final String variant = systemLocale.getVariant();
+            final boolean hasVariant = !TextUtils.isEmpty(variant);
+            if (hasLanguage && hasCountry && hasVariant) {
+                systemLocaleLanguageCountryVariant = new Locale(language, country, variant);
+            } else {
+                systemLocaleLanguageCountryVariant = null;
+            }
+            if (hasLanguage && hasCountry) {
+                systemLocaleLanguageCountry = new Locale(language, country);
+            } else {
+                systemLocaleLanguageCountry = null;
+            }
+            if (hasLanguage) {
+                systemLocaleLanguage = new Locale(language);
+            } else {
+                systemLocaleLanguage = null;
+            }
+        } else {
+            systemLocaleLanguageCountryVariant = null;
+            systemLocaleLanguageCountry = null;
+            systemLocaleLanguage = null;
+        }
+
+        final ArrayList<Locale> locales = new ArrayList<>();
+        if (systemLocaleLanguageCountryVariant != null) {
+            locales.add(systemLocaleLanguageCountryVariant);
+        }
+
+        if (Locale.ENGLISH.equals(systemLocaleLanguage)) {
+            if (systemLocaleLanguageCountry != null) {
+                // If the system language is English, and the region is also explicitly specified,
+                // following fallback order will be applied.
+                // - systemLocaleLanguageCountry [if systemLocaleLanguageCountry is non-null]
+                // - en_US [if systemLocaleLanguageCountry is non-null and not en_US]
+                // - en_GB [if systemLocaleLanguageCountry is non-null and not en_GB]
+                // - en
+                if (systemLocaleLanguageCountry != null) {
+                    locales.add(systemLocaleLanguageCountry);
+                }
+                if (!LOCALE_EN_US.equals(systemLocaleLanguageCountry)) {
+                    locales.add(LOCALE_EN_US);
+                }
+                if (!LOCALE_EN_GB.equals(systemLocaleLanguageCountry)) {
+                    locales.add(LOCALE_EN_GB);
+                }
+                locales.add(Locale.ENGLISH);
+            } else {
+                // If the system language is English, but no region is specified, following
+                // fallback order will be applied.
+                // - en
+                // - en_US
+                // - en_GB
+                locales.add(Locale.ENGLISH);
+                locales.add(LOCALE_EN_US);
+                locales.add(LOCALE_EN_GB);
+            }
+        } else {
+            // If the system language is not English, the fallback order will be
+            // - systemLocaleLanguageCountry  [if non-null]
+            // - systemLocaleLanguage  [if non-null]
+            // - en_US
+            // - en_GB
+            // - en
+            if (systemLocaleLanguageCountry != null) {
+                locales.add(systemLocaleLanguageCountry);
+            }
+            if (systemLocaleLanguage != null) {
+                locales.add(systemLocaleLanguage);
+            }
+            locales.add(LOCALE_EN_US);
+            locales.add(LOCALE_EN_GB);
+            locales.add(Locale.ENGLISH);
+        }
+        return locales;
+    }
 }
diff --git a/core/tests/inputmethodtests/src/android/os/InputMethodTest.java b/core/tests/inputmethodtests/src/android/os/InputMethodTest.java
index a50fb54..31a4703 100644
--- a/core/tests/inputmethodtests/src/android/os/InputMethodTest.java
+++ b/core/tests/inputmethodtests/src/android/os/InputMethodTest.java
@@ -51,11 +51,15 @@
     private static final Locale LOCALE_FR = new Locale("fr");
     private static final Locale LOCALE_FR_CA = new Locale("fr", "CA");
     private static final Locale LOCALE_HI = new Locale("hi");
+    private static final Locale LOCALE_JA = new Locale("ja");
     private static final Locale LOCALE_JA_JP = new Locale("ja", "JP");
     private static final Locale LOCALE_ZH_CN = new Locale("zh", "CN");
     private static final Locale LOCALE_ZH_TW = new Locale("zh", "TW");
     private static final Locale LOCALE_IN = new Locale("in");
     private static final Locale LOCALE_ID = new Locale("id");
+    private static final Locale LOCALE_TH = new Locale("ht");
+    private static final Locale LOCALE_TH_TH = new Locale("ht", "TH");
+    private static final Locale LOCALE_TH_TH_TH = new Locale("ht", "TH", "TH");
     private static final String SUBTYPE_MODE_KEYBOARD = "keyboard";
     private static final String SUBTYPE_MODE_VOICE = "voice";
     private static final String SUBTYPE_MODE_ANY = null;
@@ -849,4 +853,99 @@
 
         return preinstalledImes;
     }
+
+    @SmallTest
+    public void testGetSuitableLocalesForSpellChecker() throws Exception {
+        {
+            final ArrayList<Locale> locales =
+                    InputMethodUtils.getSuitableLocalesForSpellChecker(LOCALE_EN_US);
+            assertEquals(3, locales.size());
+            assertEquals(LOCALE_EN_US, locales.get(0));
+            assertEquals(LOCALE_EN_GB, locales.get(1));
+            assertEquals(LOCALE_EN, locales.get(2));
+        }
+
+        {
+            final ArrayList<Locale> locales =
+                    InputMethodUtils.getSuitableLocalesForSpellChecker(LOCALE_EN_GB);
+            assertEquals(3, locales.size());
+            assertEquals(LOCALE_EN_GB, locales.get(0));
+            assertEquals(LOCALE_EN_US, locales.get(1));
+            assertEquals(LOCALE_EN, locales.get(2));
+        }
+
+        {
+            final ArrayList<Locale> locales =
+                    InputMethodUtils.getSuitableLocalesForSpellChecker(LOCALE_EN);
+            assertEquals(3, locales.size());
+            assertEquals(LOCALE_EN, locales.get(0));
+            assertEquals(LOCALE_EN_US, locales.get(1));
+            assertEquals(LOCALE_EN_GB, locales.get(2));
+        }
+
+        {
+            final ArrayList<Locale> locales =
+                    InputMethodUtils.getSuitableLocalesForSpellChecker(LOCALE_EN_IN);
+            assertEquals(4, locales.size());
+            assertEquals(LOCALE_EN_IN, locales.get(0));
+            assertEquals(LOCALE_EN_US, locales.get(1));
+            assertEquals(LOCALE_EN_GB, locales.get(2));
+            assertEquals(LOCALE_EN, locales.get(3));
+        }
+
+        {
+            final ArrayList<Locale> locales =
+                    InputMethodUtils.getSuitableLocalesForSpellChecker(LOCALE_JA_JP);
+            assertEquals(5, locales.size());
+            assertEquals(LOCALE_JA_JP, locales.get(0));
+            assertEquals(LOCALE_JA, locales.get(1));
+            assertEquals(LOCALE_EN_US, locales.get(2));
+            assertEquals(LOCALE_EN_GB, locales.get(3));
+            assertEquals(Locale.ENGLISH, locales.get(4));
+        }
+
+        // Test 3-letter language code.
+        {
+            final ArrayList<Locale> locales =
+                    InputMethodUtils.getSuitableLocalesForSpellChecker(LOCALE_FIL_PH);
+            assertEquals(5, locales.size());
+            assertEquals(LOCALE_FIL_PH, locales.get(0));
+            assertEquals(LOCALE_FIL, locales.get(1));
+            assertEquals(LOCALE_EN_US, locales.get(2));
+            assertEquals(LOCALE_EN_GB, locales.get(3));
+            assertEquals(Locale.ENGLISH, locales.get(4));
+        }
+
+        // Test variant.
+        {
+            final ArrayList<Locale> locales =
+                    InputMethodUtils.getSuitableLocalesForSpellChecker(LOCALE_TH_TH_TH);
+            assertEquals(6, locales.size());
+            assertEquals(LOCALE_TH_TH_TH, locales.get(0));
+            assertEquals(LOCALE_TH_TH, locales.get(1));
+            assertEquals(LOCALE_TH, locales.get(2));
+            assertEquals(LOCALE_EN_US, locales.get(3));
+            assertEquals(LOCALE_EN_GB, locales.get(4));
+            assertEquals(Locale.ENGLISH, locales.get(5));
+        }
+
+        // Test Locale extension.
+        {
+            final Locale localeWithoutVariant = LOCALE_JA_JP;
+            final Locale localeWithVariant = new Locale.Builder()
+                    .setLocale(LOCALE_JA_JP)
+                    .setExtension('x', "android")
+                    .build();
+            assertFalse(localeWithoutVariant.equals(localeWithVariant));
+
+            final ArrayList<Locale> locales =
+                    InputMethodUtils.getSuitableLocalesForSpellChecker(localeWithVariant);
+            assertEquals(5, locales.size());
+            assertEquals(LOCALE_JA_JP, locales.get(0));
+            assertEquals(LOCALE_JA, locales.get(1));
+            assertEquals(LOCALE_EN_US, locales.get(2));
+            assertEquals(LOCALE_EN_GB, locales.get(3));
+            assertEquals(Locale.ENGLISH, locales.get(4));
+        }
+    }
 }
diff --git a/services/core/java/com/android/server/TextServicesManagerService.java b/services/core/java/com/android/server/TextServicesManagerService.java
index 5bce6eb..aace66c 100644
--- a/services/core/java/com/android/server/TextServicesManagerService.java
+++ b/services/core/java/com/android/server/TextServicesManagerService.java
@@ -18,6 +18,7 @@
 
 import com.android.internal.annotations.GuardedBy;
 import com.android.internal.content.PackageMonitor;
+import com.android.internal.inputmethod.InputMethodUtils;
 import com.android.internal.textservice.ISpellCheckerService;
 import com.android.internal.textservice.ISpellCheckerSession;
 import com.android.internal.textservice.ISpellCheckerSessionListener;
@@ -61,9 +62,11 @@
 import java.io.FileDescriptor;
 import java.io.IOException;
 import java.io.PrintWriter;
+import java.util.Arrays;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.CopyOnWriteArrayList;
 
@@ -141,7 +144,7 @@
         buildSpellCheckerMapLocked(mContext, mSpellCheckerList, mSpellCheckerMap, mSettings);
         SpellCheckerInfo sci = getCurrentSpellChecker(null);
         if (sci == null) {
-            sci = findAvailSpellCheckerLocked(null, null);
+            sci = findAvailSpellCheckerLocked(null);
             if (sci != null) {
                 // Set the current spell checker if there is one or more spell checkers
                 // available. In this case, "sci" is the first one in the available spell
@@ -190,7 +193,7 @@
                         change == PACKAGE_PERMANENT_CHANGE || change == PACKAGE_TEMPORARY_CHANGE
                         // Package modified
                         || isPackageModified(packageName)) {
-                    sci = findAvailSpellCheckerLocked(null, packageName);
+                    sci = findAvailSpellCheckerLocked(packageName);
                     if (sci != null) {
                         setCurrentSpellCheckerLocked(sci.getId());
                     }
@@ -331,8 +334,7 @@
         mSpellCheckerBindGroups.clear();
     }
 
-    // TODO: find an appropriate spell checker for specified locale
-    private SpellCheckerInfo findAvailSpellCheckerLocked(String locale, String prefPackage) {
+    private SpellCheckerInfo findAvailSpellCheckerLocked(String prefPackage) {
         final int spellCheckersCount = mSpellCheckerList.size();
         if (spellCheckersCount == 0) {
             Slog.w(TAG, "no available spell checker services found");
@@ -349,6 +351,38 @@
                 }
             }
         }
+
+        // Look up a spell checker based on the system locale.
+        // TODO: Still there is a room to improve in the following logic: e.g., check if the package
+        // is pre-installed or not.
+        final Locale systemLocal = mContext.getResources().getConfiguration().locale;
+        final ArrayList<Locale> suitableLocales =
+                InputMethodUtils.getSuitableLocalesForSpellChecker(systemLocal);
+        if (DBG) {
+            Slog.w(TAG, "findAvailSpellCheckerLocked suitableLocales="
+                    + Arrays.toString(suitableLocales.toArray(new Locale[suitableLocales.size()])));
+        }
+        final int localeCount = suitableLocales.size();
+        for (int localeIndex = 0; localeIndex < localeCount; ++localeIndex) {
+            final Locale locale = suitableLocales.get(localeIndex);
+            for (int spellCheckersIndex = 0; spellCheckersIndex < spellCheckersCount;
+                    ++spellCheckersIndex) {
+                final SpellCheckerInfo info = mSpellCheckerList.get(spellCheckersIndex);
+                final int subtypeCount = info.getSubtypeCount();
+                for (int subtypeIndex = 0; subtypeIndex < subtypeCount; ++subtypeIndex) {
+                    final SpellCheckerSubtype subtype = info.getSubtypeAt(subtypeIndex);
+                    final Locale subtypeLocale = InputMethodUtils.constructLocaleFromString(
+                            subtype.getLocale());
+                    if (locale.equals(subtypeLocale)) {
+                        // TODO: We may have more spell checkers that fall into this category.
+                        // Ideally we should pick up the most suitable one instead of simply
+                        // returning the first found one.
+                        return info;
+                    }
+                }
+            }
+        }
+
         if (spellCheckersCount > 1) {
             Slog.w(TAG, "more than one spell checker service found, picking first");
         }