diff --git a/completion.go b/completion.go
index 2ae49354..0405b90d 100644
--- a/completion.go
+++ b/completion.go
@@ -21,7 +21,8 @@ var (
 	completionMargin = leftMargin + rightMargin
 )
 
-// Suggest is printed when completing.
+// Suggest represents a single suggestion
+// in the auto-complete box.
 type Suggest struct {
 	Text        string
 	Description string
@@ -29,7 +30,7 @@ type Suggest struct {
 
 // CompletionManager manages which suggestion is now selected.
 type CompletionManager struct {
-	selected  int // -1 means nothing one is selected.
+	selected  int // -1 means nothing is selected.
 	tmp       []Suggest
 	max       uint16
 	completer Completer
@@ -58,19 +59,19 @@ func (c *CompletionManager) GetSuggestions() []Suggest {
 	return c.tmp
 }
 
-// Reset to select nothing.
+// Unselect the currently selected suggestion.
 func (c *CompletionManager) Reset() {
 	c.selected = -1
 	c.verticalScroll = 0
 	c.Update(*NewDocument())
 }
 
-// Update to update the suggestions.
+// Update the suggestions.
 func (c *CompletionManager) Update(in Document) {
 	c.tmp = c.completer(in)
 }
 
-// Previous to select the previous suggestion item.
+// Select the previous suggestion item.
 func (c *CompletionManager) Previous() {
 	if c.verticalScroll == c.selected && c.selected > 0 {
 		c.verticalScroll--
@@ -88,7 +89,7 @@ func (c *CompletionManager) Next() {
 	c.update()
 }
 
-// Completing returns whether the CompletionManager selects something one.
+// Completing returns true when the CompletionManager selects something.
 func (c *CompletionManager) Completing() bool {
 	return c.selected != -1
 }
@@ -180,7 +181,7 @@ func formatSuggestions(suggests []Suggest, max int) (new []Suggest, width int) {
 	return new, leftWidth + rightWidth
 }
 
-// NewCompletionManager returns initialized CompletionManager object.
+// NewCompletionManager returns an initialized CompletionManager object.
 func NewCompletionManager(completer Completer, max uint16) *CompletionManager {
 	return &CompletionManager{
 		selected:  -1,
@@ -193,6 +194,8 @@ func NewCompletionManager(completer Completer, max uint16) *CompletionManager {
 
 var _ Completer = NoopCompleter
 
+// NoopCompleter implements a Completer function
+// that always returns no suggestions.
 func NoopCompleter(_ Document) []Suggest {
 	return nil
 }
diff --git a/prompt.go b/prompt.go
index 9fa70c3b..7a3fae3f 100644
--- a/prompt.go
+++ b/prompt.go
@@ -8,7 +8,8 @@ import (
 	"github.com/c-bata/go-prompt/internal/debug"
 )
 
-// Executor is called when user input something text.
+// Executor is called when the user
+// inputs a line of text.
 type Executor func(string)
 
 // ExitChecker is called after user input to check if prompt must stop and exit go-prompt Run loop.
@@ -18,17 +19,18 @@ type Executor func(string)
 // Exit means exit go-prompt (not the overall Go program)
 type ExitChecker func(in string, breakline bool) bool
 
-// Completer should return the suggest item from Document.
+// Completer is a function that returns
+// a slice of suggestions for the given Document.
 type Completer func(Document) []Suggest
 
-// Prompt is core struct of go-prompt.
+// Prompt is a core struct of go-prompt.
 type Prompt struct {
 	in                ConsoleParser
 	buf               *Buffer
 	renderer          *Render
 	executor          Executor
 	history           *History
-	lexer *Lexer
+	lexer             *Lexer
 	completion        *CompletionManager
 	keyBindings       []KeyBind
 	ASCIICodeBindings []ASCIICodeBind
@@ -38,12 +40,12 @@ type Prompt struct {
 	skipTearDown      bool
 }
 
-// Exec is the struct contains user input context.
+// Exec is the struct that contains the user input context.
 type Exec struct {
 	input string
 }
 
-// Run starts prompt.
+// Run starts the prompt.
 func (p *Prompt) Run() {
 	p.skipTearDown = false
 	defer debug.Teardown()
@@ -230,7 +232,8 @@ func (p *Prompt) handleASCIICodeBinding(b []byte) bool {
 	return checked
 }
 
-// Input just returns user input text.
+// Input starts the prompt, lets the user
+// input a single line and returns this line as a string.
 func (p *Prompt) Input() string {
 	defer debug.Teardown()
 	debug.Log("start prompt")