The Malayalam alphabet comes in two basic parts - the consonants and the vowels:
This looks like a lot of letters (and, as my father commented, "they all look like curly m's!"), but, luckily, they're arranged into some sensible patterns that makes it easier to keep them straight. Let's go through the basic ones, starting with the consonants.
First off, you'll notice the consonants are written as two blocks. The first one is the most structured - in fact, it's arranged as a grid. As you move down the grid, the consonants move from the back of your mouth to the front:
So, as you can see in the image, the first letter in the top row (ക) has a "ka" sound - and if you try saying this aloud, you can feel that it starts with your tongue coming off the back of your palate. In contrast, the first letter of the bottom row (പ) has a "pa" sound - and when you try saying this one aloud, you can feel that it begins with your lips (so, the very front of your mouth) parting. The intermediate rows start in intermediate places in your mouth: for example, the first letter of the second row (ച) is pronounced "cha" - which starts with your tongue leaving the mid-front region of your palate, just where it starts to flatten out as it heads towards your teeth. The first letter of the fourth row (ത) is pronounced "ta" (it's also sometimes written "tha"), and starts with your tongue leaving the flat area of your palate just behind your teeth.
There's also a pattern as you move from left to right - this time, in fact, there are two patterns on top of each other. First, as you move from the far left row to the far right row, you have an increase in what I think of as "N-ness", but which is better described as moving from a "hard start" to the letter to a "soft start":
So, as you can see above, the last letter on the left (പ) starts with a burst of air ("pa"), whereas the last letter on the right (മ) starts with your mouth/lips in almost exactly the same position, but because you don't include the burst of air as you start, the sounds comes out as "ma". Similarly, in the row directly above this one, you can feel as you say them that "ta" (ത) starts with a burst of air just like "pa", whereas the last letter in that row (ന) is pronounced "na" - again, your mouth starts in just the same position, except you leave out the burst of air. Intermediate between these two sounds is the letter ദ, which is pronounced "da" or "dha". Following the pattern, it has a softer start than "ta", but a harder one than "na".
There's another pattern as you move from left to right, also, hidden within this one. As you go from the first column to the second (or from the third to the fourth), the sounds are almost the same, except with more exhaling involved. Literally, you just say the same sound, but you push more air from your lungs as you do it, making it more forceful:
I have to admit, this is one of the parts of Malayalam I don't like - it's hard to make myself say the higher-airflow letters! Particularly when I'm trying to speak in a language I'm not comfortable with, I'm pretty shy, and my instinct is to speak very quietly - but you just can't do that and say these letters correctly. I'm working at it, though....
The other block of consonants isn't ordered like the first one - it's more just a random (to my eye) list. A majority of them fall into just a couple of groups, though, so, just for the sake of orientation, here are the three main groups I think of them as falling into:
There are three letters (ശ, ഷ and സ) that are some form of "sa" or "sha" sound; there are three letters (ര, ഴ and റ) that are "ra" sounds (at least, that's how they sound to English speakers - ഴ isn't actually thought of as a form of R by native Malayalam speakers); and there are two (ള and ല) that are forms of "La". How are there multiple Malayalam letters for roughly the same English letter, you ask? Well, we'll get to that part, later in this series of lessons! First, though, let's do the vowels.
Like the first batch of consonants, the vowels are arranged into a grid. Here, each row contains a related sound, arranged with the "short" version of the vowel sound to the left, the "long" version of that same vowel just to the right of this, and, for some vowels, a third version where the sound is slightly changed is tacked on to the far right:
It's a little bit hard to figure out how to indicate long and short versions of vowels in English, but the concept is for the most part very simple - you really do just sustain the longer vowels for longer, and with a bit more emphasis. You'll see when we get to some examples in the next couple of lessons. The "other" column is different for the two rows with members in it - for the example shown above, you can try saying "oh", "Oh", and "ow" and you can feel how the last one is sort of like the first two, but blended with some other sounds. Again, you'll get the hang of this when you start learning words.
There's one final wrinkle to this - the vowels as shown above are how they're written on their own, at the start of a word. But anytime they're following a consonant, they're thought of as "modifying" that consonant (which makes more sense when you realize that consonants are thought of as having a built in default vowel of "a" - so when I say that മ is pronounced "ma" I really mean it: as written, that letter indicates both an "m" sound and an "a" sound following it). And when a vowel is modifying a consonant, it's written differently. So, for each of the vowels, you actually need to keep in mind two different notational forms:
In the modifying forms, the dashed-circle indicates where the consonant that's being modified would go. So, if you want to turn മ ("ma") into "mo", you would write it as മൊ. The first vowel listed (അ) corresponds to the short "ah" sound, which is the default, and so it doesn't have a modifier form - if nothing else is indicated, this is the sound you use.
And, that's it! Remember, this was just an orientation - I'm not expecting you to remember any of these letters in particular; this is just so that as we learn them in depth one by one, you'll have a framework to think of them in.