There are two primary methods for typing Devanagari characters using a computer keyboard:

• Back-transliteration
• Keyboard layouts

Back-transliteration

A transliteration is a transcription of the letters of one language into another language. For instance, “aap kaise hain” is a transliteration of आप कैसे हैं.

Back-transliteration is the process of converting a transliteration back to the script of its original language, i.e., reversing the transliteration. For instance, “aap kaise hain” would be back-transliterated as “आप कैसे हैं”.

There are various software tools that can automatically back-transliterate text.

The Advantages of Back-transliteration Tools

I strongly prefer this method of typing Hindi for several reasons:

• It’s very fast; I can type Hindi words as fast as I can type English words
• Most keyboards contain English characters, so obviously it’s easier to type using the default meanings of these keys than to memorize a new keyboard layout
• Many back-transliteration tools are web-based, so it is not necessary to install special software, and they can be used from any computer
• This method is flexible; there are many ways to transliterate words, and such tools employ statistical techniques that are flexible enough to transliterate words correctly.
• Transliterated Hindi is extremely common, especially on the web, but even in printed media and handwriting. Thus it’s good to learn it, and so using back-transliteration doesn’t require an arbitrary skill like keyboard layouts do.

Transliteration Styles

Of course, there is no canonical way to transliterate a word. Words can be transliterated in many ways. For instance, the word “देवनागरी” can be transliterated as “Devanagari”, “Devnagri” or “Devnagari”. A good back-transliteration tool will convert all of these transliterations to “देवनागरी”. As another example, some people type “mein” for में, but some people type “me” or “men”; a good back-transliteration tool will correctly convert all of these transliterations to में.

By Sound

Transliterations can be according to sound: the character प is pronounced similarly to the letter “p” in English, so this choice is obvious.

By Convention

However, transliterations can also be according to convention. The letter ए is usually transliterated as “e”. The letter “e” can be pronounced this way, but it can be pronounced many other ways too. The convention is that this represents a particular sound.

As another example, the character ऐ is often transliterated as “ai” in English, which is simply a convention, since “ai” in English is generally not pronounced like ऐ.

Back-transliteration tools use sophisticated statistical techniques that enable them to be flexible enough to back-transliterate various styles. They are based on actual data gathered from various sources, so they will recognize common transliteration styles. Highly idiosyncratic styles of typing will not work well with such tools.

Particular Back-transliteration Tools

Two particular tools are notable: Google’s transliteration tools, and Quillpad.

Google’s Transliteration Tools

Google has a back-transliteration service that is integrated with several of its products, including Gmail and Blogger. In addition, there are separate web applications such as Google Translate, and Google Transliteration.

For instance, in Gmail, I have enabled a button that toggles between English and Hindi. I can then type transliterated Hindi and it will automatically convert it to Devanagari.

Usually, I simply type text into Google Translate or Google Transliteration and then copy and paste it elsewhere.

Google’s Input Tools integrate with a wide variety of Google’s products and services, such as Google Search and Google Chrome.

Google also provides an “input method editor” (IME) for Microsoft Windows.

Thus, there are a wide variety of options for typing Hindi using Google’s input tools.

Quillpad

Quillpad is a free service operated by an Indian software company, and supports a variety of Indian languages. Quillpad offers a rich editor, and supports pasting text into the editor (which enables the user to transliterate large blocks of text at once).

Typical Features of Back-transliteration Tools

These tools allow the user to select alternative back-transliterations if the software selects an unintended back-transliteration. They will remember such corrections for the duration of a session. They generally include on-screen keyboards for arbitrary text, which is usually not necessary.

Disadvantages

Back-transliteration tools do have a few minor disadvantages. Although these tools are generally very flexible, users still will probably have to adapt their typing style slightly. For instance, both Google and Quillpad will render “wo” as वो. This isn’t altogether wrong, since even some formal publications write वो. However, if वह is intended, “vah” must be typed. These tools cannot distinguish between की and कि, but this is a minor matter. In Google’s tools, I correct “ki” to कि, and when I want to type की, I type “kii”. These adaptations are relatively few and simple. Overall, using such tools is very easy.

Keyboard Layouts

Keyboard layouts are tools in the computer’s operating system that map the keys on the keyboard to Devanagari characters. I generally do not recommend such tools, since they are difficult to use. For instance, there are approximately twice as many Devanagari characters as English characters, so this implies that other keys will have to be used. Any such assignment will be fairly arbitrary, and might be hard to remember. Some layouts make it difficult to type conjuncts; they require an explicit halant every time a conjunct is needed.