diff --git a/app/src/main/java/io/github/sspanak/tt9/ime/modes/ModeWords.java b/app/src/main/java/io/github/sspanak/tt9/ime/modes/ModeWords.java
index 35247b73..d14b0fb0 100644
--- a/app/src/main/java/io/github/sspanak/tt9/ime/modes/ModeWords.java
+++ b/app/src/main/java/io/github/sspanak/tt9/ime/modes/ModeWords.java
@@ -385,11 +385,10 @@ class ModeWords extends ModeCheonjiin {
 	public boolean nextTextCase(boolean analyzeSurroundingText) {
 		boolean changed = super.nextTextCase(analyzeSurroundingText);
 
-		// Prevent lowercase at the beginning of a line when the respective setting is enabled.
 		// "analyzeSurroundingText" is true only when Shift is pressed to avoid expensive
 		// calls to getStringBeforeCursor().
-		if (analyzeSurroundingText && textCase == CASE_LOWER && language.hasUpperCase() && settings.getAutoCapitalsAfterNewline() && textField.getStringBeforeCursor(1).equals("\n")) {
-			changed = super.nextTextCase(analyzeSurroundingText);
+		if (analyzeSurroundingText && textCase == CASE_LOWER && autoTextCase.isLowerCaseForbidden(language, textField.getStringBeforeCursor())) {
+			changed = super.nextTextCase(true);
 		}
 
 		// since it's a user's choice, the default matters no more
diff --git a/app/src/main/java/io/github/sspanak/tt9/ime/modes/helpers/AutoTextCase.java b/app/src/main/java/io/github/sspanak/tt9/ime/modes/helpers/AutoTextCase.java
index 14a1855e..71268a4c 100644
--- a/app/src/main/java/io/github/sspanak/tt9/ime/modes/helpers/AutoTextCase.java
+++ b/app/src/main/java/io/github/sspanak/tt9/ime/modes/helpers/AutoTextCase.java
@@ -88,4 +88,25 @@ public class AutoTextCase {
 
 		return InputMode.CASE_DICTIONARY;
 	}
+
+
+	/**
+	 * Prevent lowercase at the beginning of a line when the respective setting is enabled,
+	 * or at the beginning of a sentence, when auto capitalization is enabled.
+	 */
+	public boolean isLowerCaseForbidden(@NonNull Language language, @NonNull String beforeCursor) {
+		if (!language.hasUpperCase()) {
+			return false;
+		}
+
+		if (settings.getAutoTextCase() && (beforeCursor.isEmpty() || Text.isStartOfSentence(beforeCursor))) {
+			return true;
+		}
+
+		if (settings.getAutoCapitalsAfterNewline() && beforeCursor.endsWith("\n")) {
+			return true;
+		}
+
+		return false;
+	}
 }