diff --git a/build.xml b/build.xml
index 123aa7c..84f60be 100644
--- a/build.xml
+++ b/build.xml
@@ -139,7 +139,7 @@
 		<!-- Test if trace expressions involving the ShiViz module work correctly. -->
 		<!-- This test expects TLC to report a liveness violation, which is why    -->
 		<!-- failonerror is off.  Instead, ant records TLC's return value in       -->
-		<!-- shiviz.return.value, which is cheked in the conditional below.        -->
+		<!-- shiviz.return.value, which is checked in the conditional below.        -->
 		<java classname="tlc2.TLC" fork="true" failonerror="false" resultproperty="shiviz.return.value">
 			<!-- Tell Java to use a garbage collector which makes TLC happy. -->
 			<jvmarg value="-XX:+UseParallelGC"/>
diff --git a/modules/ShiViz.tla b/modules/ShiViz.tla
index 1ae1ded..899a43f 100644
--- a/modules/ShiViz.tla
+++ b/modules/ShiViz.tla
@@ -20,7 +20,7 @@ INSTANCE Toolbox
 \* Host below is different to the action predicate 
 \*   CHOOSE p \in DOMAIN pc : pc[p] # pc'[p]
 \* since Host evaluates for states n and n - 1
-\* whereas the CHOOSE evalutes for states n and n + 1.
+\* whereas the CHOOSE evaluates for states n and n + 1.
 \* This difference is most easily observed by looking
 \* at off-by-one difference of the initial state.
 LOCAL FnHost ==
diff --git a/modules/tlc2/overrides/IOUtils.java b/modules/tlc2/overrides/IOUtils.java
index f1c41f3..7439b04 100644
--- a/modules/tlc2/overrides/IOUtils.java
+++ b/modules/tlc2/overrides/IOUtils.java
@@ -99,7 +99,7 @@ public synchronized static Value textSerialize(final Tool tool, final ExprOrOpAr
 			final TLCState s0, final TLCState s1, final int control, final CostModel cm) {
 		
 		final String msgInvalidParam = "Serialize error invalid parameters: ";
-		final String successmsg = "Finish writting to the file with success!";
+		final String successmsg = "Finish writing to the file with success!";
 		
 		final RecordValue opts;	
 		
@@ -142,7 +142,7 @@ public synchronized static Value textSerialize(final Tool tool, final ExprOrOpAr
 				return new RecordValue(EXEC_NAMES, new Value[] { IntValue.ValZero, new StringValue(successmsg), new StringValue("") }, false);
 				
 			} catch(Exception e) {
-				final StringValue errormsg = new StringValue("Serialize error writting to the file: "+e.toString());
+				final StringValue errormsg = new StringValue("Serialize error writing to the file: "+e.toString());
 				return new RecordValue(EXEC_NAMES, new Value[] { IntValue.ValOne, new StringValue(""), errormsg }, false);
 			}
 		}
@@ -249,7 +249,7 @@ public static Value ioEnv() throws IOException, InterruptedException {
 	
 	@TLAPlusOperator(identifier = "IOExec", module = "IOUtils", minLevel = 1, warn = false)
 	public static Value ioExec(final Value parameter) throws IOException, InterruptedException {
-		// 1. Check parameters and covert.
+		// 1. Check parameters and convert.
 		if (!(parameter instanceof TupleValue)) {
 			throw new EvalException(EC.TLC_MODULE_ONE_ARGUMENT_ERROR,
 					new String[] { "IOExec", "sequence", Values.ppr(parameter.toString()) });
@@ -267,7 +267,7 @@ public static Value ioExec(final Value parameter) throws IOException, Interrupte
 
 	@TLAPlusOperator(identifier = "IOEnvExec", module = "IOUtils", minLevel = 1, warn = false)
 	public static Value ioEnvExec(final Value env, final Value parameter) throws IOException, InterruptedException {
-		// Check env and parameters and covert.
+		// Check env and parameters and convert.
 		final RecordValue environment = (RecordValue) env.toRcd();
 		if (environment == null) {
 			throw new EvalException(EC.TLC_MODULE_ONE_ARGUMENT_ERROR,
@@ -290,7 +290,7 @@ public static Value ioEnvExec(final Value env, final Value parameter) throws IOE
 
 	@TLAPlusOperator(identifier = "IOExecTemplate", module = "IOUtils", minLevel = 1, warn = false)
 	public static Value ioExecTemplate(final Value commandTemplate, final Value parameter) throws IOException, InterruptedException {
-		// 1. Check parameters and covert.
+		// 1. Check parameters and convert.
 		if (!(commandTemplate instanceof TupleValue)) {
 			throw new EvalException(EC.TLC_MODULE_ONE_ARGUMENT_ERROR,
 					new String[] { "IOExecTemplate", "sequence", Values.ppr(commandTemplate.toString()) });
@@ -316,13 +316,13 @@ public static Value ioExecTemplate(final Value commandTemplate, final Value para
 	
 	@TLAPlusOperator(identifier = "IOEnvExecTemplate", module = "IOUtils", minLevel = 1, warn = false)
 	public static Value ioEnvExecTemplate(final Value env, final Value commandTemplate, final Value parameter) throws IOException, InterruptedException {
-		// Check env and parameters and covert.
+		// Check env and parameters and convert.
 		final RecordValue environment = (RecordValue) env.toRcd();
 		if (environment == null) {
 			throw new EvalException(EC.TLC_MODULE_ONE_ARGUMENT_ERROR,
 					new String[] { "IOEnvExecTemplate", "record", Values.ppr(env.toString()) });
 		}
-		// 1. Check parameters and covert.
+		// 1. Check parameters and convert.
 		if (!(commandTemplate instanceof TupleValue)) {
 			throw new EvalException(EC.TLC_MODULE_ONE_ARGUMENT_ERROR,
 					new String[] { "IOEnvExecTemplate", "sequence", Values.ppr(commandTemplate.toString()) });
diff --git a/tests/SequencesExtTests.tla b/tests/SequencesExtTests.tla
index c0fd0b7..97820bb 100644
--- a/tests/SequencesExtTests.tla
+++ b/tests/SequencesExtTests.tla
@@ -315,7 +315,7 @@ ASSUME(ReplaceAllSubSeqs("\t", "%%", "Properly escape the %% char") = "Properly
 ASSUME(ReplaceAllSubSeqs("\f", "%%", "Properly escape the %% char") = "Properly escape the \f char")
 ASSUME(ReplaceAllSubSeqs("\r", "%%", "Properly escape the %% char") = "Properly escape the \r char")
 
-ASSUME AssertEq(ReplaceAllSubSeqs("replaces", "%pattern%", "This %pattern% the pattern %pattern% multipe times"), "This replaces the pattern replaces multipe times")
+ASSUME AssertEq(ReplaceAllSubSeqs("replaces", "%pattern%", "This %pattern% the pattern %pattern% multiple times"), "This replaces the pattern replaces multiple times")
 ASSUME AssertEq(ReplaceAllSubSeqs("\\\\", "\\", "Properly escape the \\quotes"), "Properly escape the \\\\quotes")