There is no objective measure of the “most underrated” programming languages: the term depends on what a reader values. This reasoned shortlist focuses on languages whose history, design ideas, or fit for particular problems deserve more attention in general accounts of programming. These older programming languages are still worth learning about—not because they outrank today’s popular tools, but because they make different ways of thinking about software visible.
What makes a programming language underrated?
Here, “underrated” means that a language’s documented design ideas, historical role, or strengths in a specialized domain merit more attention than they typically receive in broad discussions. It is an editorial judgment, not a popularity ranking. The available historical sources do not establish current usage, job demand, or a measurable league table.
The five choices below cover different approaches: interactive object-oriented computing, extensible stack-based programming, fault-tolerant concurrency, array-oriented notation, and typed functional language design. Their order is editorial, not a ranking.
| Language | Problem domain | Programming model | Distinctive idea | What studying it can teach |
|---|---|---|---|---|
| Smalltalk | Interactive computing and software development environments | Dynamic, object-oriented | A language understood as part of an interactive system | How objects, tools, and an exploratory environment can shape programming |
| Forth | Direct machine control and constrained or specialized environments | Compact, stack-based, extensible | Programmers can extend the language and communicate closely with the machine | How to build a small, tailored programming environment around a task |
| Erlang | Telecommunications and systems requiring concurrency and recovery | Concurrent, fault-tolerant | Concurrency and error recovery treated as language-level concerns | How application requirements can shape language design |
| APL | Array-oriented computation | Concise, array-based notation | Operations can express computation over arrays compactly | How notation can make a different computational model natural |
| Standard ML | Typed functional programming and language design | Functional, statically typed | A combination of type inference, pattern matching, modules, exceptions, and mutable state | Where several ideas found across later language design came together |
1. Smalltalk: programming as an interactive world
Why it matters
Smalltalk’s history is not just a story about syntax or object orientation. Daniel Ingalls’s account in the ACM SIGPLAN HOPL proceedings traces its evolution from Smalltalk-72 through Squeak, including changes in technical design and in how its creators understood object orientation and personal computing. That makes Smalltalk useful to study as a language and as a system for developing software interactively.
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
- Aluminum Alloy Housing: Built with a sturdy aluminum alloy shell that aids in heat dissipation and protects against daily wear and scratches. Designed to maintain a stable and secure connection.
- Compact & Travel-Friendly: The ultra-compact design allows the adapter to stay plugged into your device without blocking adjacent ports or adding bulk, reducing wear and tear on your original USB ports.
- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
What to keep in context
It is too sweeping to say Smalltalk “invented everything.” Its history is more useful when read as an evolving set of ideas about objects, personal computing, and interactive development. Early versions ran on proprietary Xerox hardware, which limited access to those original artifacts. ACM SIGPLAN’s Dynamic Languages Symposium also describes Smalltalk among mature dynamic languages that continue to inspire new converts; that is evidence of continuing intellectual interest, not a measure of present-day adoption.
2. Forth: a small language shaped by direct control
Why it matters
Forth is a compact, stack-based language designed for close interaction with a machine and for extension by its users. The Forth 2012 Standard foreword characterizes it as a means of direct communication between people and machines, emphasizing low-level hardware access and the ability to extend the language itself. Those qualities can be valuable when a task calls for a tailored environment and close control rather than a broad, general-purpose toolkit.
A historical account from Forth, Inc. describes Charles Moore’s work at the National Radio Astronomy Observatory. In the early 1970s, a stand-alone Forth system was used to point and track a telescope, collect and record data, and support interactive analysis. That is a concrete example of a language shaped by its applications and constraints—not evidence that Forth is the best choice for general-purpose contemporary software.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
- Quick Data Transfers: Accelerate your productivity with rapid data transfers using a high-speed 5Gbps USB 3.0 port and two 480Mbps USB 2.0 ports.
- 4K HDMI Display: Enhance your visual experience with a hub capable of delivering 4K resolution at 30Hz in both mirror and extend modes. Please note that this hub is compatible with MacBook (macOS 12 and newer), Windows 10 and 11, ChromeOS, and laptops equipped with DP Alt Mode and Power Delivery. Note: This device is not compatible with Linux.
- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
Who might find it useful to study
Forth offers a close look at how a small language can become a purpose-built tool. Readers who want an introduction can consult Forth, Inc.’s Starting Forth.
3. Erlang: concurrency and recovery as core concerns
Why it matters
Erlang emerged from a practical telecommunications problem. According to the official Erlang/OTP history, researchers at Ericsson experimented with more than 20 languages before concluding that the language they needed should support concurrency and error recovery as built-in concerns. The history dates the first experiments to 1987, early external use to 1988, and work on distribution to 1993.
The Erlang/OTP academic and historical FAQ places the language’s origin in an Ericsson Computer Science Laboratory project in the second half of the 1980s and names Joe Armstrong, Robert Virding, and Mike Williams as the initial participants. This background helps explain why Erlang’s design is associated with concurrent systems and recovery: those needs were part of the problem it was created to address.
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
How to read its performance history
The Erlang history page also reports an efficiency comparison in a particular project context. That result should not be treated as a general benchmark or as a prediction of how Erlang performs in modern applications; a project-specific historical comparison cannot establish either.
4. APL: array thinking in compact notation
Why it matters
APL makes array-oriented computation central to its way of expressing programs. The ACM SIGPLAN HOPL proceedings summarize its design principles and early uses, its movement from mainframes to smaller computers and later devices, and the development of general arrays in later generations. The proceedings’ history, by Roger K. W. Hui and Morten J. Kromberg, identifies J and k as descendants of the SHARP APL family.
That long evolution is captured in a line the proceedings reproduce from the historical paper: “Although this is not the place to discuss the future, it should be remarked that the evolution of APL is far from finished.”
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
What can make it challenging
APL’s concise notation can be unfamiliar to programmers used to more conventional syntax. Its notation and keyboard conventions may also make it harder for newcomers to read or enter expressions. That is a practical learning consideration, not a measured claim about how many people find it difficult.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.5. Standard ML: a useful lens on language design
Why it matters
The ML family began with the Meta Language of the LCF theorem-proving system in the 1970s. The ACM SIGPLAN HOPL proceedings describe Standard ML as the first language to bring together the complete feature set associated with ML: polymorphic type inference, datatypes with pattern matching, modules, exceptions, and mutable state.
The proceedings also discuss how ideas from ML languages influenced later language design, including type inference, generics, pattern matching, and module systems. That makes Standard ML a useful language to study even for readers who do not plan to use it day to day: it offers a way to examine how several ideas now encountered across language design fit together. This is a statement about the ML family’s influence, not a claim that every modern language inherited each feature directly from Standard ML.
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
Which older programming languages are still worth learning about?
Choose based on the idea you want to understand, not an unsupported promise of popularity or job demand:
- Study Smalltalk to explore interactive object-oriented programming as a complete development environment.
- Study Forth to see how a compact, extensible language can address direct-control tasks.
- Study Erlang to understand a language shaped by concurrency and error recovery requirements.
- Study APL to encounter a distinct, array-oriented approach to expressing computation.
- Study Standard ML to examine a language that brings together several important ideas in typed functional design.
These histories show why the languages merit attention; they do not establish which is most widely used today. For a decision based on current ecosystem size, platform support, or career demand, dated comparative evidence would be needed.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
