Life and Love

1) programming language research is actually a VAST domain with a vaguely
defined boundary. Different researchers self-indentified with this area might
be working on completely different issues. For a typical non-PL CS student,
the area can be easily associated with some compiler construction stuff, such
as parsing or optimization, since a course on compilers is normally what we
first learned at undergrad time (remember those sleepless nights of hacking on
scanning and parsing?:-)), but in effect, this research area has some deep
reaches on both theoretical and applied ends. On the theory side, higher order
logic, formal semantics, theorem proving, type systems are all very relevant,
and that's I guess why a conference like LICS (a top conference in logic) and
POPL (arguably "the" top theory conference in PL) was mentioned by a previous
post. On the less theoretical side, program analysis/model checking, i.e. what
properties we can know of a program without running it, such as whether it is
secure or whether there might be memory leak, has always been a big topic.
There are also many projects with an experimental flavor, just like what you
see in a typical systems conference. A conference like PLDI has always been
good at this style of projects. (PLDI is a lot more than this I should say).
Of course let's not forget language design, depending on whether you are a
believer in object-orient languages or functional languages, you might have
different target conferences in mind, OOPSLA or ECOOP for OO languages, and
ICFP for functional languages. Last but not least, software engineering and
programming languages also have a lot of things overlapping each other. Many
software engineering researchers go to OOPSLA or ECOOP, and many programming
language researchers go to a conference like ICSE (a top conference in
software engineering).

2) because of 1), if you are a PL researcher, especially a Ph.D. student, the
conferences you can submit papers might be far fewer than those PL conferences
available, because each conference has its own "flavor" and the innate
characteristic of your research has more or less "disqualified" you of
publishing in certain conferences. For instance, do you expect a Ph.D student
who researches on register allocation to submit a paper on theorem proving,
or vice versa? :-)

3) conferences in PL tend to have a small number of accepted papers. The
number of papers accepted in each conference tend to be within the 20-30
range, if not fewer, and this is true as far as I know to all these high
profile conferences including POPL, PLDI, OOPSLA, ECOOP and ICFP. I have heard
from friends some top conferences in other areas might even accept 60 papers,
so I guess one such conference could cancel out 2 or 3 in PL. :-) In addition,
the aforementioned PL conferences all have a low acceptance rate. The six
conferences mentioned above seem to have never had an acceptance rate beyond
20%, and normally a lot lower.

BTW, it's really hard to estimate the number of groups in US doing programming
languages now, but I guess most schools in reasonable standing have some
professors in this area. Corporate research centers like Microsoft, IBM and
SUN all have sizable groups. Besides, Europe has always been a powerhouse in
this area. Places like INRIA France are perhaps as competitive as any research
centers on US soil, and many researchers in UK, Switzerland, Italy, Germany
and Denmark, etc, are out there with established status. So, it's actually
sweatily crowded. :-)