diff --git a/include/binary_search_tree.h b/include/binary_search_tree.h
index 5066c771..2fc544c0 100644
--- a/include/binary_search_tree.h
+++ b/include/binary_search_tree.h
@@ -31,7 +31,7 @@ namespace alg {
 		class BST {
 			private:
 				/**
-				 * binary search tree definiton.
+				 * binary search tree definition.
 				 */
 				struct treeNode {
 					KeyT 	key;			// key
diff --git a/include/dijkstra.h b/include/dijkstra.h
index d0bebe7d..5013f14f 100644
--- a/include/dijkstra.h
+++ b/include/dijkstra.h
@@ -52,7 +52,7 @@ namespace alg {
 				// all vertices
 				Graph::Adjacent * a;
 				list_for_each_entry(a, &g.list(), a_node){
-					dist[a->v.id] = LARGE_NUMBER; // set inital distance to each vertex to a large number
+					dist[a->v.id] = LARGE_NUMBER; // set initial distance to each vertex to a large number
 					(*previous)[a->v.id] =  UNDEFINED; // clear path to UNDEFINED
 					visited[a->v.id] = false; // all vertices are not visited
 					Q.push(LARGE_NUMBER, a->v.id);	// push all vertices to heap
diff --git a/include/hash_table.h b/include/hash_table.h
index 0fcdb713..1c5abd6e 100644
--- a/include/hash_table.h
+++ b/include/hash_table.h
@@ -36,7 +36,7 @@ namespace alg {
 			typedef _HashCode hash_code_fn;
 			private:
 				/**
-				 * definiton of Key-Value pair.
+				 * definition of Key-Value pair.
 				 */
 				struct HashKV {
 					key_type key;	// 32-bit key
diff --git a/include/merge_sort.h b/include/merge_sort.h
index 8a45aece..5eab291d 100644
--- a/include/merge_sort.h
+++ b/include/merge_sort.h
@@ -13,8 +13,8 @@
  *       and right part.
  *           Example: Say the input is  -10 32 45 -78 91 1 0 -16 then the left part will be  
  *           -10 32 45 -78 and the right part will be  91 1 0 6.
- *   (2) Sort Each of them seperately. Note that here sort does not mean to sort it using some other
- *            method. We already wrote fucntion to sort it. Use the same.
+ *   (2) Sort Each of them separately. Note that here sort does not mean to sort it using some other
+ *            method. We already wrote function to sort it. Use the same.
  *   (3) Then merge the two sorted parts.
  *
  * ------------
diff --git a/include/priority_queue.h b/include/priority_queue.h
index 4a8dbe28..e81edf35 100644
--- a/include/priority_queue.h
+++ b/include/priority_queue.h
@@ -75,7 +75,7 @@ namespace alg {
 					list_add(&n->node, &m_head);
 					m_count++;
 				} else {
-					// sequentially find the apropriate position
+					// sequentially find the appropriate position
 					PQNode * pos;
 					bool found = false;
 					list_for_each_entry(pos, &m_head, node) {
diff --git a/include/skiplist.h b/include/skiplist.h
index 1c330ba7..f45d4f33 100644
--- a/include/skiplist.h
+++ b/include/skiplist.h
@@ -97,7 +97,7 @@ namespace alg {
 			if(x == NULL || x->key != key) {        
 				int lvl = random_level();	// random promotion
 
-				// for nodes higer than  current max level
+				// for nodes higher than  current max level
 				// make 'header node' as it's prev
 				if(lvl > m_level) {
 					for(int i = m_level + 1; i <= lvl; i++) {
diff --git a/include/suffix_tree.h b/include/suffix_tree.h
index 23bd04d6..d738d9c3 100644
--- a/include/suffix_tree.h
+++ b/include/suffix_tree.h
@@ -24,7 +24,7 @@ class SuffixTree
 	SuffixTree(string str):test_str(str), root(test_str), active_point(&root, 0, 0), remainder(0), pos(0), active_e(0), ls() {}
 	int construct(void);
 
-	// return -1 if no such sub exist, return the beginning postion of this substring in thr original string if it exist
+	// return -1 if no such sub exist, return the beginning position of this substring in thr original string if it exist
 	int search(string sub);
 
 	// return the length of the longest prefix of sub which can be matched in suffix tree
@@ -257,7 +257,7 @@ class SuffixTree
 	int remainder;
 	// how many characters inserted?
 	unsigned int pos;
-	unsigned int active_e;	// the beginnig position of suffixes need to be inserted
+	unsigned int active_e;	// the beginning position of suffixes need to be inserted
 	char get_ele(int i) { return test_str[i]; }
 	// insert a char from pos to suffix tree
 	int insert();
@@ -266,7 +266,7 @@ class SuffixTree
 	int print_node(Node* node, int level);
 
 
-	Node* seperate_edge(Node * node, Edge* edge);
+	Node* separate_edge(Node * node, Edge* edge);
 
 	// check if we can change active node
 	bool check_active_node(void)
diff --git a/include/universal_hash.h b/include/universal_hash.h
index 29afcf7d..1b162857 100644
--- a/include/universal_hash.h
+++ b/include/universal_hash.h
@@ -63,7 +63,7 @@ namespace alg {
 	}
 
 	/**
-	 * hash an arbitary length integer.
+	 * hash an arbitrary length integer.
 	 * len, number of 32-bit integer, max len is 32
 	 */
 	static uint32_t uhash_bigint(const struct UHash * params, uint32_t * key, uint32_t len) {
diff --git a/src/suffix_tree_demo.cpp b/src/suffix_tree_demo.cpp
index 8862e9b2..d4425c68 100644
--- a/src/suffix_tree_demo.cpp
+++ b/src/suffix_tree_demo.cpp
@@ -82,7 +82,7 @@ int SuffixTree::construct(void)
 					ls.ins_link(node);
 					break;
 				}
-				Node *newnode = seperate_edge(node, a_edge);
+				Node *newnode = separate_edge(node, a_edge);
 				Edge* newedge = new Edge(pos, numeric_limits<unsigned int>::max(), test_str);
 				newnode->add_edge(newedge);
 				ls.ins_link(newnode);
@@ -106,7 +106,7 @@ int SuffixTree::construct(void)
 
 SuffixTree::Node* SuffixTree::seperate_edge(Node * node, Edge* a_edge)
 {
-	cout << "seperate the old edge here: " << (*a_edge) << endl;
+	cout << "separate the old edge here: " << (*a_edge) << endl;
 	int new_begin = a_edge->begin + get_active_length();
 	int new_end = a_edge->end;
 
@@ -175,7 +175,7 @@ using namespace std;
 
 int main()
 {
-	cout << "Begining" << endl;
+	cout << "Beginning" << endl;
 	SuffixTree st("mississippi");
 
 	cout << "Constructing..." << endl;