diff --git a/src/training/text2image.cpp b/src/training/text2image.cpp
index f1f308d30e..43c1a96a48 100644
--- a/src/training/text2image.cpp
+++ b/src/training/text2image.cpp
@@ -684,7 +684,7 @@ static int Main() {
 }
 
 int main(int argc, char** argv) {
-  // Respect enviroment variable. could be:
+  // Respect environment variable. could be:
   // fc (fontconfig), win32, and coretext
   // If not set force fontconfig for Mac OS.
   // See https://github.com/tesseract-ocr/tesseract/issues/736
@@ -693,7 +693,7 @@ int main(int argc, char** argv) {
   if (backend == NULL) {
     putenv("PANGOCAIRO_BACKEND=fc");
   } else {
-    printf("Using '%s' as pango cairo backend based on enviroment "
+    printf("Using '%s' as pango cairo backend based on environment "
            "variable.\n", backend);
   }
   tesseract::CheckSharedLibraryVersion();
diff --git a/unittest/bitvector_test.cc b/unittest/bitvector_test.cc
index 77a95e7785..54d849a3cc 100644
--- a/unittest/bitvector_test.cc
+++ b/unittest/bitvector_test.cc
@@ -28,7 +28,7 @@ class BitVectorTest : public testing::Test {
   std::string OutputNameToPath(const std::string& name) {
     return file::JoinPath(FLAGS_test_tmpdir, name);
   }
-  // Computes primes upto kPrimeLimit, using the seive of Eratosthenes.
+  // Computes primes up to kPrimeLimit, using the sieve of Eratosthenes.
   void ComputePrimes(BitVector* map) {
     map->Init(kPrimeLimit + 1);
     TestAll(*map, false);
@@ -101,7 +101,7 @@ class BitVectorTest : public testing::Test {
   }
 };
 
-// Tests the seive of Eratosthenes as a way of testing set/reset and I/O.
+// Tests the sieve of Eratosthenes as a way of testing set/reset and I/O.
 TEST_F(BitVectorTest, Primes) {
   BitVector map;
   ComputePrimes(&map);
diff --git a/unittest/commandlineflags_test.cc b/unittest/commandlineflags_test.cc
index da391e30c1..d767bc80dd 100644
--- a/unittest/commandlineflags_test.cc
+++ b/unittest/commandlineflags_test.cc
@@ -23,7 +23,7 @@ STRING_PARAM_FLAG(bar_string, "bar", "String flag for testing");
 BOOL_PARAM_FLAG(foo_bool, false, "Bool flag for testing");
 BOOL_PARAM_FLAG(bar_bool, false, "Bool flag for testing");
 // A flag whose name is a single character, tested for backward
-// compatability. This should be selected to not conflict with existing flags
+// compatibility. This should be selected to not conflict with existing flags
 // in commontraining.cpp.
 STRING_PARAM_FLAG(q, "", "Single character name");
 
diff --git a/unittest/indexmapbidi_test.cc b/unittest/indexmapbidi_test.cc
index 74bde1a6eb..25f9eabf28 100644
--- a/unittest/indexmapbidi_test.cc
+++ b/unittest/indexmapbidi_test.cc
@@ -29,7 +29,7 @@ class IndexMapBiDiTest : public testing::Test {
   std::string OutputNameToPath(const std::string& name) {
     return file::JoinPath(FLAGS_test_tmpdir, name);
   }
-  // Computes primes upto kPrimeLimit, using the seive of Eratosthenes.
+  // Computes primes up to kPrimeLimit, using the sieve of Eratosthenes.
   void ComputePrimes(IndexMapBiDi* map) {
     map->Init(kPrimeLimit + 1, false);
     map->SetMap(2, true);
@@ -63,7 +63,7 @@ class IndexMapBiDiTest : public testing::Test {
   }
 };
 
-// Tests the seive of Eratosthenes as a way of testing setup.
+// Tests the sieve of Eratosthenes as a way of testing setup.
 TEST_F(IndexMapBiDiTest, Primes) {
   IndexMapBiDi map;
   ComputePrimes(&map);
diff --git a/unittest/normstrngs_test.cc b/unittest/normstrngs_test.cc
index 44e6cc7eb6..76ba4dac57 100644
--- a/unittest/normstrngs_test.cc
+++ b/unittest/normstrngs_test.cc
@@ -310,7 +310,7 @@ TEST(NormstrngsTest, IsWhitespace) {
   EXPECT_TRUE(IsWhitespace('\t'));
   EXPECT_TRUE(IsWhitespace('\r'));
   EXPECT_TRUE(IsWhitespace('\n'));
-  // U+2000 thru U+200A
+  // U+2000 through U+200A
   for (char32 ch = 0x2000; ch <= 0x200A; ++ch) {
     SCOPED_TRACE(StringPrintf("Failed at U+%x", ch));
     EXPECT_TRUE(IsWhitespace(ch));
diff --git a/unittest/pango_font_info_test.cc b/unittest/pango_font_info_test.cc
index a95683fd25..875b57b38f 100644
--- a/unittest/pango_font_info_test.cc
+++ b/unittest/pango_font_info_test.cc
@@ -143,7 +143,7 @@ TEST_F(PangoFontInfoTest, CanDropUncoveredChars) {
   EXPECT_EQ(1, font_info_.DropUncoveredChars(&word));
   EXPECT_EQ("oice", word);
 
-  // Dont drop non-letter characters like word joiners.
+  // Don't drop non-letter characters like word joiners.
   const char* kJoiners[] = {
       "\u2060",  // U+2060 (WJ)
       "\u200C",  // U+200C (ZWJ)
@@ -192,7 +192,7 @@ TEST_F(FontUtilsTest, DoesFindAvailableFonts) {
 TEST_F(FontUtilsTest, DoesDetectMissingFonts) {
   // Only bold italic face is available.
   EXPECT_FALSE(FontUtils::IsAvailableFont("Arial"));
-  // Dont have a ttf for the Courier family.
+  // Don't have a ttf for the Courier family.
   EXPECT_FALSE(FontUtils::IsAvailableFont("Courier"));
   // Pango "synthesizes" the italic font from the available Verdana Regular and
   // includes it in its list, but it is not really loadable.
diff --git a/unittest/tatweel_test.cc b/unittest/tatweel_test.cc
index 98baf8a5d2..4f7ed92042 100644
--- a/unittest/tatweel_test.cc
+++ b/unittest/tatweel_test.cc
@@ -50,7 +50,7 @@ TEST_F(TatweelTest, DictIgnoresTatweel) {
 
 TEST_F(TatweelTest, UnicharsetLoadKeepsTatweel) {
   // This test verifies that a load of an existing unicharset keeps any
-  // existing tatweel for backwards compatability.
+  // existing tatweel for backwards compatibility.
   string filename = TestDataNameToPath("ara.unicharset");
   EXPECT_TRUE(unicharset_.load_from_file(filename.c_str()));
   int num_tatweel = 0;