diff --git a/README.md b/README.md
index 49ee8b7d..4bc9eb71 100644
--- a/README.md
+++ b/README.md
@@ -5,19 +5,18 @@ line-bot-sdk-php
 
 SDK of the LINE Messaging API for PHP.
 
-About LINE Messaging API
+About the LINE Messaging API
 --
 
-Please refer to the official API documents for details.
+See the official API documentation for more information.
 
-en: [https://devdocs.line.me/en/](https://devdocs.line.me/en/)
-
-ja: [https://devdocs.line.me/ja/](https://devdocs.line.me/ja/)
+English: [https://devdocs.line.me/en/](https://devdocs.line.me/en/)<br>
+Japanese: [https://devdocs.line.me/ja/](https://devdocs.line.me/ja/)
 
 Installation
 --
 
-The LINE messaging API SDK can be installed with [Composer](https://getcomposer.org/).
+Install the LINE Messaging API SDK using [Composer](https://getcomposer.org/).
 
 ```
 $ composer require linecorp/line-bot-sdk
@@ -28,21 +27,21 @@ Getting started
 
 ### Create the bot client instance
 
-Instance of bot client is a handler of the Messaging API.
+The bot client instance is a handler of the Messaging API.
 
 ```php
 $httpClient = new \LINE\LINEBot\HTTPClient\CurlHTTPClient('<channel access token>');
 $bot = new \LINE\LINEBot($httpClient, ['channelSecret' => '<channel secret>']);
 ```
 
-The constructor of bot client requires an instance of `HTTPClient`.
-This library provides `CurlHTTPClient` as default.
+The constructor of the bot client requires an instance of `HTTPClient`.
+This library provides `CurlHTTPClient` by default.
 
 ### Call API
 
-You can call API through the bot client instance.
+You can call an API through the bot client instance.
 
-Deadly simple sample is following;
+A very simple example:
 
 ```php
 $response = $bot->replyText('<reply token>', 'hello!');
@@ -50,7 +49,7 @@ $response = $bot->replyText('<reply token>', 'hello!');
 
 This procedure sends a message to the destination that is associated with `<reply token>`.
 
-More advanced sample is below;
+A more advanced example:
 
 ```php
 $textMessageBuilder = new \LINE\LINEBot\MessageBuilder\TextMessageBuilder('hello');
@@ -64,25 +63,24 @@ if ($response->isSucceeded()) {
 echo $response->getHTTPStatus . ' ' . $response->getRawBody();
 ```
 
-`LINEBot#replyMessage()` takes reply token and `MessageBuilder`.
-This method sends message that is built by `MessageBuilder` to the destination.
+`LINEBot#replyMessage()` takes the reply token and `MessageBuilder`.
+The method sends a message that is built by `MessageBuilder` to the destination.
 
 Components
 --
 
 ### MessageBuilder
 
-Type of message depends on the type of instance of `MessageBuilder`.
-That means this method sends text message if you pass `TextMessageBuilder`,
-on the other hand it sends image message if you pass `ImaageMessageBuilder`.
+The type of message that is sent depends on the type of instance of `MessageBuilder`.
+For example, the method sends a text message if you pass `TextMessageBuilder` and it sends an image message if you pass `ImaageMessageBuilder`.
 
-If you want detail information of `MessageBuilder`, please refer `\LINE\LINEBot\MessageBuilder` and the namespace.
+For more detailed information on `MessageBuilder`, see `\LINE\LINEBot\MessageBuilder` and the namespace.
 
-Other methods that take `MessageBuilder` behave the same.
+Other methods that take `MessageBuilder` behave in the same way.
 
 ### Response
 
-Methods that call API returns `Response`.  Response has three methods;
+Methods that call API returns `Response`. Response has three methods;
 
 - `Response#isSucceeded()`
 - `Response#getHTTPStatus()`
@@ -91,23 +89,23 @@ Methods that call API returns `Response`.  Response has three methods;
 - `Response#getHeader($name)`
 - `Response#getHeaders()`
 
-You can use these method to check response status and take response body.
+You can use these methods to check the response status and take response body.
 
 #### `Response#isSucceeded()`
 
-This method returns the boolean value. Return value represents "request is succeeded or not".
+Returns a Boolean value. The return value represents whether the request succeeded or not.
 
 #### `Response#getHTTPStatus()`
 
-This method returns the HTTP status code of response.
+Returns the HTTP status code of a response.
 
 #### `Response#getRawBody()`
 
-This method returns the body of response as raw (i.e. byte string).
+Returns the body of the response as raw data (a byte string).
 
 #### `Response#getJSONDecodedBody()`
 
-This method returns the body that is decoded as JSON. This body is an array.
+Returns the body that is decoded in JSON. This body is an array.
 
 #### `Response#getHeader($name)`
 
@@ -119,16 +117,16 @@ This method returns all of the response headers as string array.
 
 ### Webhook
 
-LINE's server sends user action (message, image, location and etc.) to your bot server.
+LINE's server sends user actions (such as a message, image, or location) to your bot server.
 Request of that contains event(s); event is action of the user.
 
-Flow of webhook handling is like following;
+The following shows how the webhook is handled:
 
 1. Receive webhook from LINE's server.
 2. Parse request payload by `LINEBot#parseEventRequest($body, $signature)`.
 3. Iterate parsed events and some react as you like.
 
-We provides examples of this flow:
+The following examples show how webhooks are handled:
 
 - [EchoBot: Route.php](/examples/EchoBot/src/LINEBot/EchoBot/Route.php)
 - [KitchenSink: Route.php](/examples/KitchenSink/src/LINEBot/KitchenSink/Route.php)
@@ -136,44 +134,42 @@ We provides examples of this flow:
 More information
 --
 
-Please check [official API documents](#about-line-messaging-api) and PHPDoc.
-If you first time to use this library, we recommend to see `examples` and PHPDoc of `\LINE\LINEBot`.
+For more information, see the [official API documents](#about-line-messaging-api) and PHPDoc.
+If it's your first time using this library, we recommend taking a look at `examples` and the PHPDoc of `\LINE\LINEBot`.
 
 Hints
 --
 
 ### Examples
 
-This repository contains two examples of LINE Messaging API.
+This repository contains two examples of how to use the LINE Messaging API.
 
 #### [EchoBot](/examples/EchoBot)
 
-A simple sample implementation. This application reacts to text message that is from user.
+A simple sample implementation. This application reacts to text messages that are sent from users.
 
 #### [KitchenSink](/examples/KitchenSink)
 
-A full-stack (and a bit complex) sample implementation. That will show you practical usage of LINE Messaging API.
+A full-stack (and slightly complex) sample implementation. This application demonstrates a practical use of the LINE Messaging API.
 
 ### PHPDoc
 
-This library provides PHPDoc. That will helps you to know usages of methods.
-
-This library can generate pretty documents by [apigen](http://www.apigen.org/). Please try:
+This library provides PHPDoc to describe how to use the methods. You can generate the documentation using [apigen](http://www.apigen.org/) using the following command.
 
 ```
 $ make doc
 ```
 
-When HTML documents will be put on `docs/`.
+The HTML files are generated in `docs/`.
 
-### Official API documents
+### Official API documentation
 
-[Official API documents](#about-line-messaging-api) shows the detail of Messaging API and fundamental usage of SDK.
+[Official API documents](#about-line-messaging-api) shows the detail of  Messaging API and fundamental usage of SDK.
 
 Notes
 --
 
-### How to switch HTTP client implementation?
+### How to switch the HTTP client implementation
 
 1. Implement `\LINE\LINEBot\HTTPClient`
 2. Pass the implementation to the constructor of `\LINE\LINEBot`
@@ -188,29 +184,29 @@ Requirements
 For SDK developers
 --
 
-### How to run tests?
+### How to run tests
 
-Please use `make test`.
+Use `make test`.
 
-### How to execute [PHP_CodeSniffer](https://github.com/squizlabs/PHP_CodeSniffer)?
+### How to execute [PHP_CodeSniffer](https://github.com/squizlabs/PHP_CodeSniffer)
 
-Please use `make phpcs`.
+Use `make phpcs`.
 
-### How to execute [PHPMD](https://phpmd.org/)?
+### How to execute [PHPMD](https://phpmd.org/)
 
-Please use `make phpmd`.
+Use `make phpmd`.
 
-### How to execute them all??
+### How to execute them all
 
 `make`
 
-See Also
+See also
 --
 
 ### [line-bot-sdk-tiny](./line-bot-sdk-tiny)
 
-Deadly simple SDK (subset) of the LINE Messaging API for PHP.
-line-bot-sdk-tiny provides simple interface and functions so it is useful to try and learn the LINE Messaging API.
+A very simple SDK (subset) for the LINE Messaging API for PHP.
+line-bot-sdk-tiny provides a simple interface and functions which makes it a good way to learn how to use the LINE Messaging API.
 
 License
 --
@@ -230,4 +226,3 @@ WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 License for the specific language governing permissions and limitations
 under the License.
 ```
-
diff --git a/examples/EchoBot/README.md b/examples/EchoBot/README.md
index 0a183394..61e47b5d 100644
--- a/examples/EchoBot/README.md
+++ b/examples/EchoBot/README.md
@@ -1,11 +1,11 @@
 line-echo-bot-sample
 ==
 
-A sample echo bot implementation of LINE Messaging API.
+A sample echo bot implementation of the LINE Messaging API.
 
-This project is using [Slim framework](http://www.slimframework.com/).
+This project uses the [Slim framework](http://www.slimframework.com/).
 
-Getting Started
+Getting started
 --
 
 ```
@@ -24,7 +24,7 @@ Entry point of this application.
 
 ### [src/LINEBot/EchoBot/Route.php](./src/LINEBot/EchoBot/Route.php)
 
-Core logic of this application that uses LINE BOT API.
+Core logic of this application that uses the LINE Messaging API.
 
 License
 --
@@ -44,4 +44,3 @@ WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 License for the specific language governing permissions and limitations
 under the License.
 ```
-
diff --git a/examples/KitchenSink/README.md b/examples/KitchenSink/README.md
index 1723bf64..c3f932d2 100644
--- a/examples/KitchenSink/README.md
+++ b/examples/KitchenSink/README.md
@@ -1,11 +1,11 @@
 line-bot-sample
 ==
 
-A full-stack LINE Messaging API sample implementation. This sample will show you practical usage of LINE Messaging API.
+A full-stack LINE Messaging API sample implementation. This sample shows you a practical use of the LINE Messaging API.
 
-This project is using [Slim framework](http://www.slimframework.com/).
+This project uses the [Slim framework](http://www.slimframework.com/).
 
-Getting Started
+Getting started
 --
 
 ```
@@ -24,7 +24,7 @@ Entry point of this application.
 
 ### [src/LINEBot/KitchenSink/Route.php](./src/LINEBot/KitchenSink/Route.php)
 
-Core logic of this application that uses LINE BOT API.
+Core logic of this application using the LINE Messaging API.
 
 ### [Event handlers](./src/LINEBot/KitchenSink/EventHandler)
 
@@ -35,17 +35,17 @@ Notes
 
 ### Temporary directory
 
-This application downloads multimedia files on `./public/static/tmpdir/`.
-`./run.sh` wrapper removes such contents on shutting down the PHP server.
+This application downloads multimedia files to `./public/static/tmpdir/`.
+The `./run.sh` wrapper removes this content on shut down of the PHP server.
 
 ### Base URL
 
 This application serves downloaded multimedia files.
 
-Default, this app constructs URL of such content with `\Slim\Http\Request->getUri()->getBaseUrl()` as base URL.
-Unfortunately this processing doesn't work correctly if this app runs on reverse-proxied environment.
+By default, this app constructs URLs for the content with `\Slim\Http\Request->getUri()->getBaseUrl()` as the base URL.
+Unfortunately this process doesn't work correctly if this app runs on a reverse-proxied environment.
 
-If you get such symptom, please configure base URL as you like => [UrlBuilder](./src/LINEBot/KitchenSink/EventHandler/MessageHandler/Util/UrlBuilder.php)
+If you encounter this problem, configure the base URL to whatever you like using [UrlBuilder](./src/LINEBot/KitchenSink/EventHandler/MessageHandler/Util/UrlBuilder.php)
 
 License
 --
@@ -65,4 +65,3 @@ WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 License for the specific language governing permissions and limitations
 under the License.
 ```
-
diff --git a/line-bot-sdk-tiny/README.md b/line-bot-sdk-tiny/README.md
index 5d608634..22095b02 100644
--- a/line-bot-sdk-tiny/README.md
+++ b/line-bot-sdk-tiny/README.md
@@ -1,25 +1,24 @@
 line-bot-sdk-tiny
 ==
 
-Deadly simple SDK (subset) of the LINE Messaging API for PHP.
+A very simple SDK (subset) for the LINE Messaging API for PHP.
 
-Description (and Motivation)
+Description (and motivation)
 --
 
-[line-bot-sdk-php](https://github.com/line/line-bot-sdk-php) is a full-stack implementation of the LINE Messaging API SDK.
-That SDK uses serious OOP interface and functions. It provides API client, message builder, HTTP client, event parser and more useful components.
+[line-bot-sdk-php](https://github.com/line/line-bot-sdk-php) is a full-stack implementation of the LINE Messaging API SDK, which uses an OOP interface and functions. It provides an API client, a message builder, an HTTP client, an event parser and other useful components.
 
-On the other hand, line-bot-sdk-tiny provides simple interface and functions. This SDK contains a part of the API function (not full function).
+On the other hand, line-bot-sdk-tiny provides a simple interface and functions. It contains a part of the API functions (not full function).
 
-This SDK is provided by only one file, so it is easy to bring `LINEBotTiny.php` to your environment and require that from your script.
-And of course you can also copy & paste this SDK.
+This SDK contains only one file, so it is easy to add `LINEBotTiny.php` to your environment and require that from your script.
+And of course, you can also copy and paste this SDK.
 
 Example
 --
 
 See [echo_bot](./echo_bot.php).
 
-When you run this example, please never forget to set your channel access token and channel secret.
+When running this example, make sure that you have set your Channel access token and Channel secret.
 
 Requirements
 --
@@ -44,4 +43,3 @@ WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 License for the specific language governing permissions and limitations
 under the License.
 ```
-