With this piece I'm going to separate liberalism where I am on the Center-Left of the American political spectrum, from not just Marxism/Communism, but what's called classical liberalism or what and most other people at least today call libertarianism.
Liberalism or liberal democracy, is about individual rights, equal rights, civil rights, equal justice, equal opportunity and yes limited government. Liberals aren't anti-government which is what a lot of modern Libertarians seem to be today. Liberals just don't want big government running people's lives for them and replace individualism with a big central government. And even using big government to try to tell people what they should think and how they can talk with other people. What language is acceptable and so-forth.
Liberalism is the ultimate color, race, ethnic, and gender-blind society. Because it believes in individualism and people should be treated exactly as that as individuals. And don't believe people should be rewarded or punished based on race, ethnicity, or gender. Unlike Socialists even Democratic Socialists and Communists today, who believe minorities should be rewarded over majorities, because of their race and ethnicity and they would simply argue because European-Americans especially men were rewarded because of their race, ethnicity, and gender in the past. And it's time for racial and ethnic minorities, as well as women of all racial and ethnic backgrounds should be reward based on those factors today.
Whether you want to call them Marxists, Socialists, or Communists, or even Democratic Socialists, Socialists today have very different views from Liberals and don't think liberalism and liberal democracy goes far enough in seeing that the needs of the society and public are met. And don't trust individualism and freedom, opportunity, and even education for the masses, enough to see that everyone's needs are met. And believe you need a big centralized government and perhaps just one government for the entire society, to be used to meet the needs of that masses. And believe that individual freedom and individualism, even the ability for people to think and speak for themselves, as dangerous. Because they see it as the freedom to make mistakes that society will have to pay for. And for the rich will just richer and everyone else will be left behind.
When you're talking about liberalism versus socialism and communism, you're talking about individualism versus collectivism and even statism. Liberals trust educated individuals to be able to self-govern themselves and meet their own needs and be able to take care of themselves. With a limited government to regulate how people interact with each other, but not how we govern ourselves. Socialists and Communists, put their faith in government especially the central state, to see that needs of the masses are taken care and no one is left behind and has to go without. When you're comparing liberalism with socialism, you're talking about individualism and freedom, versus statism.