Update README.md

README.md

@@ -1,32 +1,33 @@
-## How to compile and build SilentPhone
+## How to Compile and Build SilentPhone
 
-SilentPhone consists of two major parts: the Android Java modules and their
-associated layout files, resources files, and generated source and resource
-files. The second part is C/C++ based the phone engine which includes the SIP,
-RTP, ZRTP, TLS, and codec handling among some other functions. The Java part
-uses standard JNI techniques to communicate with the C/C++ parts.
+SilentPhone consists of two major parts. The first comprises the Android
+Java modules and their associated layout files, resources files, and
+generated source and resource files. The second part, the phone engine,
+includes the SIP, RTP, ZRTP, TLS, and codec handling, along with some
+other functions. It is based on C/C++. The Java part uses standard JNI
+techniques to communicate with the C/C++ parts.
 
 
 ### Prerequisites
 
 This short description assumes that you have a good understanding of the
 Android SDK, the Android NDK, and their build procedures.
 
-To compile and build SilentPhone you require a full Android development
+To compile and build SilentPhone you need a full Android development
 environment that includes the Android Java SDK and the Android NDK (Native
-Development Kit). Because SilentPhone shall support Android API 10
-(Gingerbread 2.3.x) make sure you also download and install the necessary SDK
-modules. Furthermore I recommend to use the Eclipse Android SDK extensions.
+Development Kit). Because SilentPhone supports Android API 10 (Gingerbread
+2.3.x), make sure you also download and install the necessary SDK modules.
+We also recommend that you use the Eclipse Android SDK extensions.
 
 
 ### Directory structure
 
 SilentPhone uses a set of sources that must be compiled and linked
 together. To simplify development we have set up a specific directory
-structure that contains the sources and build files. In the following figure
-_$SRC\_ROOT_ denotes the root directory of this specific directory layout. The
-figure does not show every directory, only the top level and relevant
-directories.
+structure that contains the sources and build files. In the following
+figure _$SRC\_ROOT_ denotes the root directory of this specific layout.
+The figure does not show every directory in the tree, only the top level
+and relevant subdirectories.
 
     $SRC_ROOT
      |
@@ -82,58 +83,55 @@ directories.
 
 **NOTES:** 
 
-  - Depending on the development environment you may either use the
+  - Depending on the development environment, you may use either the
     `libs/libzrtptivi-3.0.0` directory or the main `zrtpcpp` directory. The `libs`
-    subdirectory shall contain a stable version of the ZRTP/SRTP sources and the
+    subdirectory shall contain a stable version of the ZRTP/SRTP sources, and the
     `zrtpcpp` directory may contain a development version. In any case the ZRTP
     directories must contain the non-public extensions for the Tivi client.
-  - The directory name `scandroid` is not fixed and you may choose a different
+  - The directory name `scandroid` is not fixed, and you may choose a different
     name. However, this directory shall be at this position in the directory
     structure. 
   - The directory names _tivi_, _zrtpcpp_, and _libzrtptivi-3.0.0_ are not
     fixed. If you use different names you must adapt the names in the Android
     NDK build files.
 
 
-### Building the SilentPhone client from exising Git repository
+### Building the SilentPhone client from the existing Git repository
 
 SilentPhone's Git repository contains all necessary shared libraries to build
-the required shared library and to install it. After cloning the repository
+the required shared library, and to install it. After cloning the repository
 you should perform a build for the shared libraries to make sure all libraries
 are installed in their correct places. 
 
-After that step you can build SilentPhone. Either setup an Eclipse Android
+After that step you can build SilentPhone. Either set up an Eclipse Android
 project or use the `ant` command line tools to generate the application
 package.
 
-**NOTE:** After the SilentPhone code basis becomes more stable we may put the
-libraries also into the Git repository. This saves the extra build step. 
+**NOTE:** As the SilentPhone code basis becomes more stable, we may put the
+libraries into the Git repository as well. This saves the extra build step. 
 
 
 ### Building the shared libraries
 
-After you built the library once it's usually not necessary to re-build it,
-except you need to fix a problem inside the library code.
+After you've built the library once, it isn't usually necessary to re-build it,
+except if you need to fix a problem in the library code.
 
 The directory `scandroid/jni` contains the build files to compile and link the
-shared libraries for SilentPhone. Depending on your directory setup and naming
-you need to adapt some lines in `jni/Android.mk`. The build files assumes the
-shown directory structure.
+shared libraries for SilentPhone. Depending on your directory setup and naming,
+you may need to adapt some lines in `jni/Android.mk`. (The build files assume
+the directory structure that is shown in the diagram.)
 
 The `Android.mk` file contains two `ifeq` sections that show how to define the
-path names for different environments. Use this as a template to setup your
+path names for different environments. Use this as a template to set up your
 own path names.
 
-If required you may also adapt the line that defines `ZRTP_SRC_PATH` to point
+If necessary, you may also adapt the line that defines `ZRTP_SRC_PATH` to point
 to the correct ZRTP source directory. Some comments in `Android.mk` already
 show two different configurations.
 
-After you adapted the build files you may just run `ndk-build` from the
+After you've adapted the build files, you can just run `ndk-build` from the
 command line. The NDK build script copies the shared libraries to their
 correct places inside the Android project. Now you can build the SilentPhone
-client with either the Eclipse Android extensions and with the `ant` command
-line tool.
-
-
-
+client with either the Eclipse Android extensions or the `ant` command line
+tool.