They are two different tools. Some of what each does will overlap with the other, but each has it's strengths and weaknesses.
InDesign is a page-layout application. It's purpose is to combine text and images to create pages, similar to the way pages were created with cut-and-paste before it was done in computers. Blocks of text and images can be moved around on a page and placed where you want.
Word is a word processing application. It is used to create documents also, but placing text in a particular position on a page is not what it is designed to do. It emulates a typewriter in that you start at the top of a page and end at the bottom. You can tab or skip lines, but having a block of text that you can move around until it looks good to you isn't what it was designed for. If you want an image, you have to place it within the flow of text (which you can also do in ID), but you can't just put it where you want and move it without effecting other aspects of the page.
Word is good for composing text which can be imported into InDesign, and while Word can make some good looking pages itself, it's use as a final product for high-end printing is limited. There are probably some good articles, videos or other comparisons you can search for, so you might want to look there as well as here.
What are you using your work for. I think that this is the first question that need's to be answered.
And asian languages will be use in same document and same paragraph.
"Asian languages" covers a lot of territory. I handle a lot of Chinese, Vietnamese, Burmese, Lao, and Khmer in both InDesign and Word, and smaller amounts of pretty much Any Asian Script You Care To Name. I think that both Migintosh and bnyhoff (hi there, MVP with one post ) have asked you really good questions; answers to these questions will help us help you figure out which application is more suited to your work.
For what it's worth, I have my "Asian" language experts work in Word, and then place & manipulate their work in InDesign. I do this because it is eighteen billion times easier to manage twelve languages (or two, or twenty) in ID than it is to do so in Word. However, I do feel that it's easier for beginners to handle that kind of work in Word. So if you have a single project, and you're asking us this question because you have been advised to use ID, and you never expect to work on a multilingual project ever again, then skip ID and just use Word. If, on the other hand, you envision a future with many such projects, then dive in and start learning to use InDesign right away. But don't expect to have a perfect project the first time; InDesign's learning curve is steep.
Thanks for giving the time.
Actually the type of work is dictionary with IPA pronunciation . Looking hard to do that. I know msword like back of my hand but i was decide to choose indesign for paragraph and character styles. What indesign will help to write both languages and maintain the formatting over the msword.
And one more thing how to write IPA language is there any special method to write that. or any font is available, someone advised me to use PEL Phonetic font but I didn't find that on any site. I'm following british method.
I know IPA (for singing in multiple languages), and while I tend to only handwrite it, I can understand your dilemma of moving from Word to InDesign: the ASCII character numbers are different in ID. That being said,.....
I have mostly stopped using Word because the features I was so comfortable with have changed a lot since I first began using it in 1988. (Bill Gates, are you listening?) My biggest thrill was jumping from CS3 to CS5 a couple years ago and discovering that all the features worked the same way or even better. That is how software evolution should be!
What I suggest is getting an official IPA font that InDesign will be able to identify. I know there is at least one out there, because I looked some time ago but never bought it because I didn't think I would use it much. (I don't think Adobe carries such, but they've got a lot, so it's worth checking.) If it's a different font developer, ask if the font will work in InDesign before you buy. And I wouldn't worry about the price. It sounds like this is something you will use a lot, anyway, and it will pay you back with ease of use.
The advantage of doing your IPA work in InDesign is that it is very easy to space type lines exactly where you want them; the Paragraphs pallet is right there on the screen. The flexibility is awesome.
But maybe the biggest case for InDesign is the print industry. If you are going to publish a paper book rather than an e-book, I can tell you that most print shops hate Word, because I asked a few shops before I bought CS3 what they like to work with. ID was at the top of the list. Do it all in Word and you may have a hard time finding a print shop that will do business with you.
I am ALWAYS coming to these forums to ask questions, and this is the first time I've answered one (which I stumbled upon by accident, btw). The forum people here are great, and I am not in a position to give back the way they do. So I hope this helps!
ceilr, very good. A couple of footnotes, if you don't mind ;)
".. the ASCII character numbers are different in ID .."
Bad, OLD style IPA fonts need you to enter an 'E' or '@' for a schwa, an 'O' for an open o, an 'N' for an eng, and so on. Each font had its own 'encoding'; changing the font to another made virtually *all* IPA characters render wrong or not at all, and you have to change them manually to the right ones, for your other font.
Also: copying text with IPA characters and pasting it elsewhere looses the font, and thus the 'meaning' of these characters. Also: exporting to HTML or PDF does not work. (PDF appears to work until you try and copy text out of that.)
InDesign does not use ASCII, it uses Unicode. It's the same principle, though, only way (way) bigger. All IPA characters have a dedicated Unicode codepoint; the same for *all* (Unicode) fonts. Changing the font to another may 'loose' a character if the new font doesn't contain it, but if you apply a font that does, you'll get the right ones. Guaranteed. (For a correctly encoded font. Most, nowadays, are.)
".. an official IPA font that InDesign will be able to identify .." InDesign does not identify a font as such, but .. you can safely try! As per above: if an IPA character has been entered in Unicode encoding, you can't ever loose it.
I don't think any of Adobe's fonts that come with ID have any IPA characters at all (perhaps the odd one has an IPA schwa), but you will find on your system, whether Mac OS X or Windows, that lots of "system fonts" have a full complement of IPA's. Ones that I am sure of: Times New Roman (huge, huge set, very complete), Arial, Calibri. Arial Unicode MS is extremely complete but alas, only Regular (I use this mainly for math symbols).
If you are going to look for a complementary set of IPA characters for another font, make sure to only and exclusively use ones that are encoded as Unicode -- modern versions of Charis SIL, SIL Doulos, or Gentium, for example.
Uh, what he said
There are some funky versions of Gentium out there, and some of them have (had) critical output problems. But that's what I'd advise to someone who needed to handle IPA in InDesign.
Joel, I found myself mulling over the How to enter sub-question. Since all I do is typeset others' writings, I hardly ever have to enter any IPA myself. Even if the original text used a Bad, Bad Font, I use Find&Change -- then I only have to enter each character *once*. Nowadays most writers use correct characters in TNR, Arial UC or Lucida UC, and so it mostly comes down to "change the font and be done with it" for me.
Well, Theun, I just asked my coworker (a Real Academic Linguist™) how to key in IPA today and he had no idea. In his defense, he was a Real Academic Linguist back in the 1990s so he had to think for a minute to remember what you'd call a "widget" in OS 9 in 1997.
I know that users of SIL's Toolbox often use a keyboard that was made with Microsoft Keyboard Layout Creator (here's a link). I also know that said keyboard was, ah, imperfect. I am a lightly-seasoned MSKLC user myself and it's possible - not easy, but possible - to make a keyboard that will encode characters in hard-to-use ways, and quite difficult to get it to function perfectly in all environments.
But, like you, I mostly handle Other People's Prose so I'd rather just do some kind of scripted FInd/Change operation to fix poorly encoded or keyed text.
So it's back to the ol' Glyphs panel.
I amended Peter Kahrel's Compose script (http://www.kahrel.plus.com/indesign/compose.html) to 1. accept Unicode values in hex, and 2. insert the requested character immediately into either the Find or the Replace field -- the most common operations. If I need a Unicode value, rather than browsing the Glyphs panel (why doesn't it have a Search field? It already knows all the correct names!), I just do a quick Google. 
My repertoire of Other People's Prose () is too large to warrant a separate script for every single Bad Encoding I have encountered over the years; I would probably have so many versions that looking the right one up would cost me even more time.
 One of InDesign's many files contain the full Unicode names, in true unicode.org style IN FULL CAPS, for more characters than I can count. The file is heavily compressed of course -- there are thousands of characters, with lots of repetitive strings -- but I found out how to decompress it. One of my long-term ideas is to write a script that allows searching for (parts of) character names, the way you can in the fabulous UnicodeChecker (http://earthlingsoft.net/UnicodeChecker/).
Sounds cool! Possible to share your modified script?
AnneMarie, Peter didn't mind but he noted the following improvements:
He updated his original version with similar functionality: entering both 4- and 5-digit Unicode hex numbers (mine only "does" 4), added some more "overstrike" characters to the Auto-accent creator, and his version automatically inserts the character in both Text and GREP Find What fields if the cursor is not "in" text.
Mine (aptly renamed compose[jw].jsx; download from my site) has ...
1. more predefined character combinations to immediately insert the correct (precomposed) Unicode character
2. all HTML standard names; 'prime' inserts a prime, 'deg' a degree, 'times' a multiplication, and so on
3. checkboxes for Put in Find/Put in Change (for the Text find&change only)
-- and it does not do anything when the cursor is not inside text.
So there is some overlap and some differences in our functions.