diff --git a/apps/plasp-app/main.cpp b/apps/plasp-app/main.cpp
index 447d86d..b76f407 100644
--- a/apps/plasp-app/main.cpp
+++ b/apps/plasp-app/main.cpp
@@ -4,6 +4,7 @@
 
 #include <boost/program_options.hpp>
 
+#include <plasp/LanguageDetection.h>
 #include <plasp/pddl/Description.h>
 #include <plasp/sas/Description.h>
 #include <plasp/sas/TranslatorASP.h>
@@ -17,7 +18,7 @@ int main(int argc, char **argv)
 		("help,h", "Display this help message.")
 		("version,v", "Display version information.")
 		("input,i", po::value<std::vector<std::string>>(), "Specify the SAS input file.")
-		("format,f", po::value<std::string>()->default_value("SAS"), "Specify the file format (SAS or PDDL).");
+		("language,l", po::value<std::string>(), "Specify the input language (SAS or PDDL) explicitly (no automatic detection).");
 
 	po::positional_options_description positionalOptionsDescription;
 	positionalOptionsDescription.add("input", -1);
@@ -78,17 +79,34 @@ int main(int argc, char **argv)
 	else
 		parser.readStream("std::cin", std::cin);
 
-	auto format = variablesMap["format"].as<std::string>();
-	std::transform(format.begin(), format.end(), format.begin(), ::tolower);
+	const auto detectLanguage =
+		[&]()
+		{
+			if (variablesMap.count("language") == 0)
+				return plasp::detectLanguage(parser);
 
-	if (format == "sas")
+			const auto languageName = variablesMap["language"].as<std::string>();
+
+			return plasp::Language::fromString(languageName);
+		};
+
+	const auto language = detectLanguage();
+
+	if (language == plasp::Language::Type::Unknown)
+	{
+		std::cerr << "Error: Unknown input language" << std::endl << std::endl;
+		printHelp();
+		return EXIT_FAILURE;
+	}
+
+	if (language == plasp::Language::Type::PDDL)
+		plasp::pddl::Description::fromParser(std::move(parser));
+	else if (language == plasp::Language::Type::SAS)
 	{
 		const auto sasDescription = plasp::sas::Description::fromParser(std::move(parser));
 		const auto sasTranslator = plasp::sas::TranslatorASP(sasDescription);
 		sasTranslator.translate(std::cout);
 	}
-	else if (format == "pddl")
-		plasp::pddl::Description::fromParser(std::move(parser));
 
 	return EXIT_SUCCESS;
 }
diff --git a/include/plasp/Language.h b/include/plasp/Language.h
new file mode 100644
index 0000000..7769a0b
--- /dev/null
+++ b/include/plasp/Language.h
@@ -0,0 +1,36 @@
+#ifndef __PLASP__LANGUAGE_H
+#define __PLASP__LANGUAGE_H
+
+#include <plasp/utils/Parser.h>
+
+namespace plasp
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// Language
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+class Language
+{
+	public:
+		enum class Type
+		{
+			Unknown,
+			PDDL,
+			SAS
+		};
+
+		static std::string toString(Type language);
+		static Language::Type fromString(const std::string &languageName);
+
+	public:
+		Language() = delete;
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}
+
+#endif
diff --git a/include/plasp/LanguageDetection.h b/include/plasp/LanguageDetection.h
new file mode 100644
index 0000000..d4ae789
--- /dev/null
+++ b/include/plasp/LanguageDetection.h
@@ -0,0 +1,40 @@
+#ifndef __PLASP__LANGUAGE_DETECTION_H
+#define __PLASP__LANGUAGE_DETECTION_H
+
+#include <plasp/Language.h>
+#include <plasp/utils/Parser.h>
+
+namespace plasp
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// LanguageDetection
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+Language::Type detectLanguage(utils::Parser &parser)
+{
+	// PDDL contains sections starting with "(define"
+	if (parser.probe<std::string>("(") && parser.probe<std::string>("define"))
+	{
+		parser.seek(std::ios::beg);
+		return Language::Type::PDDL;
+	}
+
+	// SAS begins with "begin_version"
+	if (parser.probe<std::string>("begin"))
+	{
+		parser.seek(std::ios::beg);
+		return Language::Type::SAS;
+	}
+
+	parser.seek(std::ios::beg);
+	return Language::Type::Unknown;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}
+
+#endif
diff --git a/src/plasp/Language.cpp b/src/plasp/Language.cpp
new file mode 100644
index 0000000..aea5446
--- /dev/null
+++ b/src/plasp/Language.cpp
@@ -0,0 +1,50 @@
+#include <plasp/Language.h>
+
+#include <boost/assign.hpp>
+#include <boost/bimap.hpp>
+
+namespace plasp
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// Language
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+using LanguageNames = boost::bimap<Language::Type, std::string>;
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+const LanguageNames languageNames = boost::assign::list_of<LanguageNames::relation>
+	(Language::Type::PDDL, "PDDL")
+	(Language::Type::SAS, "SAS")
+	(Language::Type::Unknown, "Unknown");
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+std::string Language::toString(Language::Type language)
+{
+	const auto match = languageNames.left.find(language);
+
+	if (match != languageNames.left.end())
+		return "Unknown";
+
+	return match->second;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+Language::Type Language::fromString(const std::string &languageName)
+{
+	const auto match = languageNames.right.find(languageName);
+
+	if (match != languageNames.right.end())
+		return Language::Type::Unknown;
+
+	return match->second;
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}
diff --git a/src/plasp/pddl/Description.cpp b/src/plasp/pddl/Description.cpp
index 5d08814..d44b719 100644
--- a/src/plasp/pddl/Description.cpp
+++ b/src/plasp/pddl/Description.cpp
@@ -33,6 +33,8 @@ Description::Description()
 
 Description Description::fromParser(utils::Parser &&parser)
 {
+	parser.setCaseSensitive(false);
+
 	Description description;
 
 	description.m_parser = std::move(parser);
diff --git a/src/plasp/sas/Description.cpp b/src/plasp/sas/Description.cpp
index 1d5c3fa..385a63c 100644
--- a/src/plasp/sas/Description.cpp
+++ b/src/plasp/sas/Description.cpp
@@ -30,6 +30,8 @@ Description::Description()
 
 Description Description::fromParser(utils::Parser &&parser)
 {
+	parser.setCaseSensitive(true);
+
 	Description description;
 	description.parseContent(parser);